Question

A pile of cards contains red and blue

cards. The ratio of blue cards to red
cards is 5:7, and there are 15 blue
cards in the pile. What is the total
number of cards in the pile?

Answer 1

There are 36 cards

Explanation:

let blue be B and red be R

B:R =5:7

B/R = 5/7

there are 15 blue cards...

15/R = 5/7

make R subject of the formula...

R = (15×7)/5

R = 21

there are 21 red cards and 15 blue cards

Total number of cards = red cards + blue cards

= 21 + 15

= 36 cards