Question

A student solved this problem and said the answer is 5\8 pounds.

Gino has 3 7\8 pounds of grapes. He has 2 1\4 pounds of green grapes and the rest are red grapes. How many pounds of red grapes does Gino have?

Is the student's answer reasonable?

A.
Yes, the answer is reasonable.

B.
No, the answer is not reasonable. It should be a bit more than 1 1/2 pounds.

C.
No, the answer is not reasonable. It should be about 6 pounds.

D.
No, the answer is not reasonable. It should be a bit more than 2 pounds.

Answer 1

1 3/8 lbs. 2 1/2 = 2 4/8. (8/8 is 1 lb) 2 4/8 + 8/8 = 3 4/8 add 3/8 to equal 3 7/8. You have added 1 3/8 lb to 2 1/2 lb to make 3 7/8 lbs.

Answer 2

B. No, the answer is not reasonable. It should be a bit more than 1 1/2 pounds.

Explanation:

We have been given that Gino has
`3(7)/(8)` pounds of grapes. He has
`2(1)/(4)` pounds of green grapes and the rest are red grapes. A student solved this problem and said the answer is
`(5)/(8)` pounds.

Let us solve the given problem by subtracting
`2(1)/(4)` from
`3(7)/(8)`.

`3(7)/(8)-2(1)/(4)`

`(3*8+7)/(8)-(2*4+1)/(4)`

`(31)/(8)-(9)/(4)`

`(31)/(8)-(9*2)/(4*2)`

`(31)/(8)-(18)/(8)`

`(31-18)/(8)`

`(13)/(8)`

`1(5)/(8)`

Since
`1(5)/(8)` is greater than
`1(1)/(2)`, therefore, option B is the correct choice.