Mary and her brother john collect foreign coins. mary has four times the number of coins that john has. together they have 200 foreign coins.

x + 4x = 150

5x = 150  

x = 30

John has x = 30 coins

Mary has 4x = 4*30 = 120 coins.Let the number of coins John has be "x".

The the number of coins Mary has is "4x"

John has 40 coin and Mary has 160 coins because 40 times 4 equals 160 and 160 plus 40 equals 200 so Mary has 160 and John has 40

set each factor equal to 0

4x-3 = 0

2x-1 = 0

solve for x.

4x-3=0

4x=3

x= 3/4

solve for x. 

2x-1= 0

2x= 1

x= 1/2

your answer should be 1/2 is less than or equal to x and 3/4 is greater than or equal to x