NikunjC
I like the solution - it’s helpful. Hello,|I have a question,
I assumed the cookies got by dad was X.
Since the son at a fifth of it,
Son at x/5
left for others 4x/5
Then at dinner, the 4x/5 was further divided by a 5.
giving us 4x/25
so son ate x/5 + 4x/25 and the rest ate 4*4x/25 = 16x/25.
And none of the option was fulfilling the 9:16 ratio.
Why was my approch wrong ?
Your math setup is fine, but the interpretation is off.
When you say the others together ate 16x/25, you’re mixing total eaten by
all four others with the amount eaten
per person. The question asks for the number eaten
by each other member, not the total eaten by all of them.
Each of the other four gets 4x/25, while the son eats x/5 + 4x/25 = 9x/25. So the correct ratio is (9x/25) : (4x/25) = 9:4 (son :
each other), not 9:16 (son :
all others). That’s why your ratio didn’t match the options.
Hope it's clear.