Question

Mr. Richardson is driving to a town 85 miles away. He drives 35 miles per hour for 2 hours before stopping for lunch. He drives 6 more miles and stops for gas. Which expression shows how many miles Mr. Richardson has left to drive?

85 - (35 x 2) - 6
85 - 35 - 2 - 6
(85 - 35) x 2 - 6
85 - 35 + 2 - 6

Answer 1

(a) 85 - (35 x 2) - 6

Explanation:

The miles Mr. Richardson has left to drive will be the difference between the distance to his goal and the miles he has alread driven. The relation between distance, speed, and time can be used to find the miles he drove before lunch.

__

before lunch

distance = speed × time

miles before lunch = (35 mi/h) × (2 h) = (35 × 2) mi

total driven

The total miles driven before stopping for gas will be ...

miles before stopping for gas = (miles before lunch) + (6 more miles)

= 35 ×2 +6 . . . miles

miles remaining

Then the remaining miles are ...

remaining = trip miles - miles driven

= 85 -(35 ×2 +6)

= 85 - (35 ×2) -6 . . . . . miles left to drive