Final answer:
Marsha spent a total of $14.97 on socks after receiving $5.03 in change from $20. Dividing this amount by the 3 pairs of socks she bought, we find that each pair cost $4.99.
Step-by-step explanation:
To determine the cost of each pair of socks, we need to find out the total amount Marsha spent before receiving change.
She was given $5.03 in change after paying with a $20 bill.
The total amount spent on socks, therefore, is $20 - $5.03 = $14.97.
Since Marsha bought 3 pairs of socks and each pair costs the same amount,
we'll divide the total spent by the number of pairs to find the cost per pair. $14.97 ÷ 3 = $4.99 per pair of socks.