Sandra has some money she spends 2/7 of it on a book & she spends 2/5 of the remaining money on a bag Sandra has $15 left how much did she have to start

Answer 1

amount of her money --- x
after spending 2/7 of it, she has (5/7)x left
then she spends (2/5) of that, or (2/5)(5/7)x

total amount spent = (2/7)x + (10/35)x
= (2/7)x + (2/7)x = (4/7)x

so (3/7)x = 15
3x = 105
x = 35 <------ money she started with

check:
she spends (2/7)(35) or 10
leaving her with 25
she spends (2/5) of that or 10
leaving her with 15
my answer is correct