Question

9 ice creams cost Rs. 67.50. What will 10 ice creams cost?

Answer 1

Hint: Using the given information find the cost of 1 ice cream by using the unitary method. Now, multiply both sides of the relation by 10 and simplify the right-hand side to find the total cost of 10 ice creams.

Complete step-by-step solution:
Here, we have been provided with the information that the cost of 9 ice creams is Rs. 67.50 and we have to find the cost of 10 ice creams. So, we have,
Cost of 9 ice creams $=Rs.67.50$
So, applying the unitary method and dividing both sides with 9, we get
$\Rightarrow $ cost of 1 ice cream $=Rs.\dfrac{67.50}{9}$
$\Rightarrow $ cost of 1 ice cream $=Rs.7.5$
 Now, multiplying both sides with 10, we get,
$\Rightarrow $ cost of 10 ice cream$=Rs.7.5\times 10$
$\Rightarrow $ cost of 10 ice cream$=Rs.75$
Hence, the total cost of 10 ice creams is Rs. 75.

Note: One may note that we have applied the basic unitary method to solve the question. Actually, this question is from the topic ‘ratio and proportion’. There can be another method also to solve the question. What we can do is we will assume the cost of 10 ice creams as ‘x’ rupees. Now, we will write the given information in proportion form as 9 ice creams: Rs. $9:67.50::10:x$ ice creams: Rs. x, which is equal to the expression :- $\dfrac{9}{67.50}=\dfrac{10}{x}$. Hence, by cross multiplication, we will simplify the expression and get the value of x.