Question

The prices of a scooter and a TV are in the ratio 7:5 If the scooter costs Rs 8000 more than a TV set then the price of a TV set is
A) Rs. 20000
B) Rs. 24000
C) Rs. 28000
D) Rs. 32000

Answer 1

Hint: Ratio are mathematical entities that help in comparison of numbers. In other words a ratio can be defined as a relationship between two numbers that helps in defining the quantity of the first number with the second number.

Complete step-by-step answer:
Let the price of a scooter be 7x and of a T.V. be 5x. Then
\[ \Rightarrow 7x:5x = 8000:TV\]
The difference between the two prices is 7x-5x,
\[ \Rightarrow 7x - 5x = 8000\]
Isolate the variable on one side of the equation.
When the variable is multiplied by a coefficient in the final stage, multiply both sides of the equation by the reciprocal of the coefficient.
\[ \Rightarrow x = \dfrac{{8000}}{2} = 4000\]
If the unknown number is in the denominator we can use another method that involves the cross product. The cross product is the product of the numerator of one of the ratios and the denominator of the second ratio.
Therefore, price of scooter is 7x=7×4000= Rs. 28000
And the price of T.V. set is 5x=5×4000=Rs. 20000
 So, option (A) is correct answer

Note: The numbers forming the ratio are called terms. The numerator, “7”, in this case, is known as the antecedent and the denominator, “5”, in this case, is known as the consequent. When reading the question we note that scooter is mentioned first and then T.V., which implies numerator “7” denotes the scooter and “5” denotes T.V. is denominator.