Answer:
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
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