Question

one tenth of the cars in a car park yellow arrives and now one ninth of the cars yellow. How many cars on now in the car park?​

Answer 1

Answer:

Step-by-step explanation:

First let's assume there are total X cars in the park out of which Y are yellow.

Also it is given that 1/10th of total cars are yellow, i.e. 0.1 times of total cars are yellow-

(1/10)X = Y

(0.1)X = Y

When the new car arrives total number of cars in the park = X +1.

Now it is given that after the new car arrives, 1/9th of total cars are yellow. Here comes the important part, pay attention.

1/9 = 0.1110.111 is greater than 0.1 therefore 1/9 is greater than 1/10.

Now since yellow cars have become 1/9 times that of total number of cars after the new car arrives, we can conclude that number of yellow cars has increased therefore new car was a yellow car. If you understand this then the solution is pretty straight forward.So now after arrival of the new car which is yellow, the case is as follow-

Total no. Of cars = X + 1

Total no. Of yellow cars = Y + 1

(1/9)(X +1) = Y+1

We also another equation from the first case - (1/10)X = Y

Solving these two linear equations with 2 variables, we get -

Y = 8 and X = 80

Therefore there were 80 cars before the arrival of new car out of which 8 were yellow. After arrival of the new car we have total 81 cars out of which 9 are yellow.

Answer 2

here's your answer hope it helps