8,400 miles.
400 / 21 = 19 gallons.19 x 4.00 = $76.00
19 with remainder 1.
400 / 2 * (10 + 11) 200 * 21 = 4.200
400 -21 = 379
21 minutes 120 mph = 120 miles in 60 minutes = 2 miles in 1 minute 42 is 2 times 21 so 1 minute times 21 is 21 minutes
100-400 or so
Diameter of the circle: 21/pi = 6.685 miles rounded to 3 decimal places
13.04879
Approx. 21 400 000 inhabitants now.
21 miles
Three times.
The answer is 21. 21 X 21=441 and that's between 400 and 450