Question

Shweta is competing in a group stair-climbing relay challenge with two of her friends. They will take turns climbing the stairs of two of the tallest buildings of the city. The three of them each plan to climb an equal number of stairs, and Shweta will go first. The first building has $s$ stairs, and the second building has $3639$ stairs. During the race, Shweta faces anaemia and is only able to complete $75\%$ of her goal. What is the total number of stairs that she climbs?

• A. $0.75(\frac{1}{3}s+1213)$
• B. $0.75(\frac{1}{3}s+3639)$
• C. $75(\frac{1}{3}s+1213)$
• D. $75(\frac{1}{3}s+3639)$

Answer 1

The correct option is A $0.75(\frac{1}{3}s+1213)$

Start with the building for which we know the number of stairs.

The friends are each planning to climb $3639÷3=1213$ stairs.

Since $1,213$ must be a part of the correct answer, eliminate (B) and (D).

Given that Dalia will complete only $75\%$ of her goal,

Dalia's total must be multiplied by $75\%$ or $0.75$. This eliminates (C).

The correct answer is $0.75(\frac{1}{3}s+1213)$ (A).