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The number of ways to choose 2 pens from 4 pens can be calculated using the combination formula ( \binom{n}{r} ), where ( n ) is the total number of items and ( r ) is the number of items to choose. Here, ( n = 4 ) and ( r = 2 ). Thus, the calculation is ( \binom{4}{2} = \frac{4!}{2!(4-2)!} = \frac{4 \times 3}{2 \times 1} = 6 ). Therefore, there are 6 ways to choose 2 pens from 4.
What else can I help you with?
Suppose you buy several pens at a discount store. All the pens are the same price and you buy as many pens as the cost (in cents) of each pen. The pens cost a total of 1.44. How many pens did you buy?
Let the cost of each pen be ( x ) cents. Since you buy ( x ) pens, the total cost can be expressed as ( x \times x = x^2 ) cents. Given that the total cost is 1.44 dollars, which is 144 cents, we have the equation ( x^2 = 144 ). Solving for ( x ), we find ( x = 12 ). Therefore, you bought 12 pens.
There are p pens in a pack 2 of them don't work. write an expression for the number of working pens in a pack?
If there are ( p ) pens in a pack and 2 of them don't work, the expression for the number of working pens in the pack is ( p - 2 ). This represents the total number of pens minus the non-functioning ones.
How many different ways can you write a fraction that has a numerator of 2 as a sum of fractions?
Infinitely many ways, since if you have found one way then take one of the fractions and replace it by an equivalent fraction. Repeat for ever.
How many different ways can 40 be written as a sum of 2 positive prime numbers?
Three ways. 3 + 37 11 + 29 17 + 23
How many backpacks out of 38 contained none of the three writing instruments?
First, I would like to say that the whole question is not here. The question states: upon examining the contents of 38 backpacks, it was found that 23 contained a black pen, 27 contained a blue pen, and 21 contained a pencil, 15 contained both a black pen and a blue pen, 12 contained both a black pen and a pencil, 18 contained both a blue pen and a pencil and 10 contained all three items. How many backpacks contained none of the three writing instruments? OK I will explain this the best I can! Starting out, their are 10 backpacks that contain all the items. 12 contained both a black and blue pen. You would subtract 10 from 12; therefore there are 2 backpacks that contain only black and blue pens. 18 contain both a blue pen and a pencil. subtract 10 from 18 and you get 8. 15 contained both a black pen and a blue pen. You would subtract 10 from 15 and you get 5. There are 23 with black pens. So you would do 23 - (5+10+2)= 6. There are 6 backpacks that contain only black pens. There are 27 that contain blue pens. So you would do 27 - (5+10+8) = 4. There are 4 backpacks that contain only blue pens. There are 21 backpacks that contain a pencil. You would do 21 - (2+10+8) = 1. All together, there a 6 that contain only black pens, 5 that contain only black and blue pens, 4 that contain only blue pens, 10 that contain all three items, 2 that contain only black pens and pencils, 8 that contains only blue pens and pencils, and 1 that contains only 1 pencil. So you would add 6+5+4+10+8+2+1= 36. There are 38 backpacks, so you would subtract 36 from 38. There are 2 backpacks that contain none of the three writing instruments. Ashfords quiz says this is right.
How many different ways can you bring 2 calculators 3 pens and 4 pencils to class?
24 ways. :)
How many ways can 2 candies be chosen out of 5 candies?
10
How many ways can 2 people be chosen from a class of 20?
20C2 = 190
In how many ways can 4 boys be chosen from six?
The answer is 6C4 = 6*5/(2*1) = 15
2 students have to be chosen as monitor in a class of 36 how many ways to done this?
36 x 35/2 ie 630
How many ways can a committee consisting of a lead second and alternate be chosen out of 309?
309*308/2 = 47586
How many moles of pens do you have if you have 1.204x1024 pens?
1.204*1024 pens * (1 mole pens/6.022*1023 pens) = 1.9993 molesTherefore, 1.204*1024 pens is about 2 moles of pens.
How many ways can you choose 2 books from the 6 on the shelf?
20, without replacing the first book chosen. 25 with replacing it.
How many different 5-card hands with 3 red cards and 2 black cards can be made from a standard 52-card deck?
There are 26 red cards and 26 black cards. 3 red cards can be chosen in 26C3 ways 2 black cards can be chosen in 26C2 ways The required answer is 26C3 X 26C2 ways. Answer: 1067742 S Suneja
If 2 pens cost 59 what will 4 pens cost?
The answer is 118
There are p pens in a pack 2 of them don't work. write an expression for the number of working pens in a pack?
If there are ( p ) pens in a pack and 2 of them don't work, the expression for the number of working pens in the pack is ( p - 2 ). This represents the total number of pens minus the non-functioning ones.
What is the best deal 5 pens for 38.99 or 2 pens for 15.99?
5 pens for 38.99 is the better deal.
