Final answer:
To estimate the pounds of grapes Martin's friend bought, we approximated 12 3/5 pounds to 13 pounds and calculated 3/8 of 13 to get about 4.5 pounds.
Step-by-step explanation:
When estimating how many pounds of grapes Martin's friend bought, we look at Martin's initial purchase of 12 3/5 pounds of grapes. To estimate using compatible fractions, we want to find a fraction close to 3/8 that multiplies easily with the quantity Martin bought. Since 12 3/5 is close to 13 pounds, and 13 is close to 8 (which is a multiple of 3/8), we can use these numbers to estimate.
Martin's friend bought 3/8 of Martin's grapes. So, we first simplify 12 3/5 to a fraction that is easier to work with:
- Approximate 12 3/5 pounds as 13 pounds.
- Calculate 3/8 of 13 by multiplying:
(3/8) × 13 ≈ 3 × 1.5 ≈ 4.5 (since 1/8 of 8 is 1, and 1/8 of 13 is about 1.5).
Therefore, Martin's friend approximately bought 4.5 pounds of grapes.