A nurse mixes two drugs with saline solution to fill a 100 m

A nurse mixes two drugs with saline solution to fill a 100 milliliter IV bag. Drug X is so weak that there are supposed to be 15 more milliliters than drug Y. After adding the correct amount of drug X, the nurse accidentally added three times as much of drug Y as he was supposed to. He realizes that there are actually 3 more milliliters of drug Y than drug X. How many milliliters of drug Y were supposed to go in the bag?

Solution

let amount of durg X be x ,amount of durg Y be y

there are supposed to be 15 more milliliters than drug Y

x=15+y---------------->(1)

nurse accidentally added three times as much of drug Y as he was supposed to and He realizes that there are actually 3 more milliliters of drug Y than drug X

3y-x=3---------------->(1)

solve (1),(2)

3y-(15+y)=3

3y-15-y=3

2y=18

y=9 millilitres

9 milliliters of drug Y were supposed to go in the bag