Except for 2 and 5, all prime numbers end in the digit 1, 3, 7 or 9.
4/1 = 2/x...4 miles to 1 hr = 2 miles to x hrs
cross multiply because this is a proportion
(4)(x) = (1)(2)
4x = 2
x = 2/4 reduces to 1/2...so she can walk 2 miles in 1/2 hr (or 30 minutes)
V = whl
V = 3 1/2 * 4 1/2 * 2
answer
3 1/2 * 4 1/2 * 2
15 3/4 * 2
the answer will be 10 just multiply the numbers