Answer:
`a)30` ${marble}$
`b)6` boys
Explanation of the steps:
Title translation:
240 marbles were shared between some boys and 3 girls. The number of marbles The girls have `3/8` of the total number of marbles.
(a) Find the number of marbles each girl has.
(b) If each boy has 25 marbles, how many boys are there?
The number of marbles the 3 girls have is:
`240× 3/8= 90` (marble)
The number of marbles each girl has is:
`90:3=30`(marble)
The number of marbles the boy has is:
`240-90=150`(marble)
The number of boys is:
`150:25=6`(boy)
Answer: `a)30 marbles`
`b)6` boys