Question

Ann has an empty cup and add 1 ounce of water per second. Bob has 12 ounces of water and drinks 2 ounces per second. After how many seconds will they have the same amount of water

Answer 1

4 seconds

Explanation:

Given

Ann has an empty cup and add 1 ounce of water per second

let the number of seconds required to fill the cup be x

let the total be y

in x seconds Ann will have x ounces of water in the cup.

so the total amount of water in Ann's cup will be

`y=x-----------1`

Bob has 12 ounces of water and drinks 2 ounces per second

also, let the number of seconds required to empty the cup be x

let the total be y

`y= 12-2x--------------2`

Step two:

equate the two equations above and solve for x

`x=12-2x`

collect like terms

`x+2x=12\\\\3x=12`

divide both sides by 3

`x=12/3\\\\x= 4 seconds`

Therefore, after about 4 seconds Ann and Bob's cup will have the same amount of water