The cost of a car is 400% greater than the cost of a bike. If there is an increase in the cost

Ques - The cost of a car is 400% greater than the cost of a bike. If there is an increase in the cost of the car is 15% and that of bike 20%. Then the total increase in the cost of the 5 cars and 10 bikes is:

A. 17.5%

B. 16(3/7)%

C. 18.5%

D. 18.25%

Solution -

Let,

The initial cost of a bike = 100x

then initial cost of a car = 100x + 400% of 100x

= 100x + (400/100) × 100x

= 100x + 400x

= 500x

Increase in the cost of the car = 15%

= 500x + (15/100) × 500x

= 500x + 75x

= 575x

Increase in the cost of the car = 20%

= 100x + (20/100) × 100x

= 100x + 20x

= 120x 

Initial cost of 10 bikes = 100x × 10

= 1000x

Initial cost of 5 cars = 500x × 5

= 2500x

New cost of 10 bikes = 120x × 10

= 1200x

New cost of 5 cars = 575x × 5

= 2875x

Change in cost of bikes = new cost - initial cost

= 1200x - 1000x

= 200x

Change in cost of cars = new cost - initial cost

= 2875x - 2500x

= 375x

Thus,

The total increase in the cost of the 5 cars and 10 bikes is = 200x + 375x

= 575x

Total initial cost = 1000x + 2500x

= 3500x

Percentage increase in the cost = (575x/3500x) × 100

= 575/35

= 16(3/7)

Hence,

The correct option is (b) 16(3/7)%.

Thank You