Question

The dishes have been sorted into cups and plates. The number of plates is four less than two times the number of cups. The dishes are 60% plates. How many cups are there?

Answer 1

The number of cups = 8 ....

Explanation:

Let x be the number of cups

Let y be the number of plates

According to the given statement:

y=2x-4 This is equation 1

Now,

60% = 0.60

y=0.60(x+y) This is equation 2

Now substitute equation 1 in equation 2.

y=0.60(x+y)

2x-4=0.60(x+2x-4)

2x-4=0.6x+1.2x-2.4

Solve the like terms:

2x-4=1.8x-2.4

2x-1.8x=4-2.4

0.2x=1.6

x=1.6/0.2

x= 8 cups

Therefore the number of cups = 8 ....