It’s actually
Bonny baked some cookies. She gave 2/5 of them and an additional 15 cookies to a neighbor. 4/9 of the remainder and an additional 10 cookies to her sister. If she was left with 40 cookies, how many cookies did she bake ?
Bonny baked some cookies. She gave 2/5 of them and an additional 15 cookies to a neighbor. 4/5 of the remainder and an additional 10 cookies to her sister. If she was left with 40 cookies, how many cookies did she bake ?
5 answers
starting with x cookies,
2/5 given, leaving 3/5 x
15 more, leaving 3/5 x - 15
4/9 of that, leaving 5/9 (3/5 x - 15)
10 more, leaving 5/9 (3/5 x - 15) - 10
so, now you know that
5/9 (3/5 x - 15) - 10 = 40
or
(x-55)/3 = 40
x = 175
2/5 given, leaving 3/5 x
15 more, leaving 3/5 x - 15
4/9 of that, leaving 5/9 (3/5 x - 15)
10 more, leaving 5/9 (3/5 x - 15) - 10
so, now you know that
5/9 (3/5 x - 15) - 10 = 40
or
(x-55)/3 = 40
x = 175
gave (2c / 5 + 15) to neighbor
remainder = c - 2c/5 - 15 = 3c/5 -15
gave sister (4/5)(3c/5 -15) + 10 = 12 c/25 - 12 + 10 = (12c - 50)/25
left with
c - (2c / 5 + 15) - (12c - 50)/25 = 40
25c/25 - 10c/25 - 375/25 -12c/25 + 50/25 = 40
3 c -325 = 25*40 = 1000
3 c = 1325
c = 442
CHECK MY QUICK ARITHMETIC!
remainder = c - 2c/5 - 15 = 3c/5 -15
gave sister (4/5)(3c/5 -15) + 10 = 12 c/25 - 12 + 10 = (12c - 50)/25
left with
c - (2c / 5 + 15) - (12c - 50)/25 = 40
25c/25 - 10c/25 - 375/25 -12c/25 + 50/25 = 40
3 c -325 = 25*40 = 1000
3 c = 1325
c = 442
CHECK MY QUICK ARITHMETIC!
Now you tell me you had a typo :)
Yes I did. Oobleck is correct