Question

A bag contains blue balls, red balls, and green balls. The number of red balls in the bag is $3$ more than the number of blue balls, whereas the number of green balls is thrice the number of red balls. If the total number of balls is $27$, find the number of green balls.

Answer 1

Let the number of blue balls be $x$.
Number of red balls $=3$ more than number of blue balls
⇒ Number of red balls $=x+3$
Number of green balls $=$ thrice the number of red balls
⇒ Number of green balls $=3(x+3)$

Total number of balls in the bag = 27
⇒ $x+(x+3)+(3x+9)=27$
⇒ $5x+12=27$
⇒ $5x=27-12$
⇒ $5x=15$
⇒ $x=\frac{15}{5}=3$

Number of green balls $=3(x+3)=3(3+3)=3\times 6=18$
Therefore, the number of green balls is 18.