There are two piles of apples. If 1 / 5 of them are taken out of pile a and put into pile B, there will be as many apples as there are in pile B. how many apples are in pile B

There are two piles of apples. If 1 / 5 of them are taken out of pile a and put into pile B, there will be as many apples as there are in pile B. how many apples are in pile B

3/5.
Suppose there are apples X in pile a and apples y in pile B, then there are:
Y + 1 / 5x = 4 / 5x, so
y = 3/5x

Put 2 / 7 of the apples in frame a into frame B. the weight of the apples in two frames is equal. How much of the weight of frame B is that of the apples in frame a?

If a is 1, B is 1-2 / 7-2 / 7 = 3 / 7
So B is 3 / 7 of A

The weight of an apple is one eighth lighter than that of an orange. How much is the weight of an apple? How much is the weight of an orange heavier than that of an apple?

(1) Seven eighths
(2) Eight out of seven

The weight of an apple is one eighth lighter than an orange. How much is the weight of an apple? How much is the weight of an orange heavier than an apple?
There should be a formula

The weight of an apple is one eighth lighter than an orange. How much is the weight of an apple? How much is the weight of an orange heavier than an apple?
1-1/8=7/8
1/8÷7/8=1/7
A: the weight of an apple is one eighth lighter than that of an orange. The weight of an apple is seven eighth of that of an orange. The weight of an orange is one seventh of that of an apple