35 miles per second is how many miles per hour?

Question

(A) 2100

(B) 7/12

(C) 0.00972

(D) 155

(E) none of these

Answer 1

When you multiply fractions like

one way to do it is multiply straight across then reduce the results 2/6 = 1/3). Another way is to "cancel". Cancelling is just recognizing that something divided by itself is one. So, since there is a 2 on top and a 2 on bottom and 2 divided by 2 is 1, we can "cancel the 2s and then multiply straight across to get 1/3 as the answer.

The same holds true for units.

because s/s = 1

Now, we just need to put in the numbers associated with those units: