Question

Pedro bought lb of red sand and lb of brown sand to refill his sand box. Both types of sand cost $4.60 a pound. How much did Pedro spend on the sand? A. $29.85 B. $31.05 C. $33.05 D. $33.75

Answer 1

b. $31.05
5.5 + 1.25 = 6.75
6.75 * $4.60 = $31.05

Answer 2

If we know that Pedro bought 1 $\frac{1}{4}$ pounds of red sand, and 5 $ \frac{1}{2}$ pounds of brown sand, and they both cost $4.60, then we just have to add the individual amounts of sand, since they cost the same.

$1 \frac{1}{4} + 5 \frac{1}{2} = 6 \frac{3}{4}$

So Pedro bought $6 \frac{3}{4}$ lbs of sand overall. Now, we just need to multiply the cost per pound by the total amount of sand he bought.

$6 \frac{3}{4} * 4.6 = 31.05$

Pedro spent $31.05 on sand, which is answer choice B.
Hope that helped =)