One can purchase 20 black crayons on Amazon by buying the black crayons in bulk as opposed to by the box which contains several different colors. One can also buy black crayons at Office Specialties.
70 crayons. 90-20=70
that's easy 20
about 50,000 crayons are made in a day. the workers must work hard.
The weight of a box of crayons is dependant on the weight of each crayon, and how many in the box For example, I have seen a box of 20 large crayons weighing 500g, so each individual crayon would be 25g!
Crayola crayons have been around for over one hundred years and first came to market in the year 1903. They were superior because of their bright colors, their cost and their coverage on paper.
You could purchase one on Ebay
One can purchase ovulation test strips from Amazon where they are available to buy for around $20. One can also purchase them from eBay or from a local pharmacy.
One can purchase a mug holder from Amazon where there a number of such items available for between $5 and $20. One can also purchase them used or new from eBay.
One can purchase a decent infrared flashlight from Amazon where there are many available to purchase between $20 and $50. One can also buy them from Best Buy and eBay.
One can purchase Canon Pixma ink from 'Best Buy' for around $20. One can also purchase this item from 'Amazon', 'Inkjetsuperstore', 'ebay' and '4inkjets'.
Here is another way to phrase the question: If 18 out of 20 customers make a purchase in a shop, and three customers are selected at random, what is the probablity that all will make a purchase? Each random customer has a 18/20 chance of being one that purchased, so the probability that all three make a purchase is 18/20*18/20*18/20=.729
One can purchase reasonably priced chemistry sets from Amazon. They sell them for as little as $15-20. One can also purchase them at good prices from Ebay and Walmart.