Dev has 9 shells. Zoe has 55 shells, Zoe gives some shells to Dev. Now zoe has 3 times as many shells as dev. How many shells does Zoe give to Dev.

number of shells zoe gives to dev = 7

number of shells zoe is left with = 55-7 = 48

number of shells dev has = 9+7=16

Step-by-step explanation:

let the initial number of shells that dev has be A, and initial number of shells that zoe has be B.

let the number of shells that zoe gives to dev be x.

after giiving x shells zoe is left with 3 times the number of shell as that of dev.

therefore number of shells with zoe = 3*number of shells with dev.

number of shells with zoe = initial shells - x = 55-x

number of shells with dev = initial shells + number of shells he gets

= 9+x

therefore (55-x) = 3 * (9+x)

55-x = 27+3x

55-27=3x+x

4x = 28

x = 7

therefore number of shells zoe gives to dev = 7

number of shells zoe is left with = 55-7 = 48

number of shells dev has = 9+7=16