+0

Math

0
227
1
+58

Ali had a certain amount of savings in the bank. In October, he spent 30% of her savings. In November, he managed to save 1/5 of the amount of money he had left. Then, he bought 2 calculators at \$15.80 each and gave 3/8 of the amount that he had left to his parents. In December, he managed to save 40% of the amount of money he had left. Finally, he had \$6219.85 in the bank. (a) How much did he give to his parents? (b) How much was his original savings in the bank?

Jun 7, 2022

#1
+128826
+1

Call S  the original amt

Amount left at the end of Oct =  .7S

Amount left at the end of Nov =   .7S / 5 = .14S

After buying two calculators  and giving (3/8)  of the money left to his parents he had

(.14S - 2(15.80)) - (3/8)[ .14S - 2(15.80) ]  =

.14S  - 31.60  - .0525S + 11.85 =

.0875S - 19.75     left

In Dec  he had    .40 [ .0875 S  - 19.75 ]  left

And this equals  6219.85

So

.40 [ .0875S - 19.75] =  6219.85

.0875S  - 19.75 =  6219.85  /.40

.0875S  -19.75 = 15,549.63

.0875S  =  15,549.63 + 19.75

.0875S  = 15,569.38

S  =   15569.38/.0875   =  \$ 177,935.77

He gave his parents  (3/8)[ .14 * 177935.77 - 31.60 ]  = \$9329.78

Jun 7, 2022