Question

at the gym, polina put 4 five-pound weights onto a barbell that weighed 22 pounds without any weights on it. if polina lifted the barbell with both arms, which expression can be used to determine the weight that each arm was lifting?
○ (4 × 5) ÷ 2 + 22
○ (4 × 5) ÷ 2 + 22
○ 22 + 4 × 5 ÷ 2
○ 22 + (4 × 5) ÷ 2

Explanation:

Step1: Find total weight of barbell and weights

First, calculate the total weight of the barbell with the added weights. The barbell itself is 22 pounds, and there are 4 five - pound weights. The total weight of the barbell and weights is \(22 + 4\times5\) (we first find the total weight of the added weights \(4\times5\) and then add the weight of the barbell 22).

Step2: Divide total weight by 2 (for two arms)

Since Polina is lifting with both arms, we need to divide the total weight by 2 to find the weight each arm is lifting. So the expression is \([22 + 4\times5]\div2\).

Answer:

\([22 + 4\times5]\div2\) (the third option)