A class contains b boys and g girls. If the number of ways of selecting 3 boys and 2 girls from the class is 168 , then b + 3 g is equal to

Step-by-step solution

Given, b  boys and g girls Also given total ways of selecting 3  boys and 2 girls which will be C 3 b × C 2 g = 168 ⇒     b b - 1 b - 2 6 × g g - 1 2 = 168 ⇒     b b - 1 b - 2 g g - 1 = 7 × 6 × 4 × 3 × 2 × 2 ⇒       b b - 1 b - 2 g g - 1 = 8 × 7 × 6 × 3 × 2 Now on comparing both side we get, b = 8 and g = 3    ⇒ b + 3 g = 8 + 9 = 17