Question

If the sales tax on a purchase worth Rs. 60 is Rs. 4.20, then what will be the sales tax on a purchase worth Rs. 150.

Answer 1

Hint: Amount of sales tax on 60 Rs. Is given to be 4.2Rs.
From this information find the amount of sales tax on 1Rs. By dividing both sides by 60.
And then multiplying by 150 on both sides you will get an amount of sales tax on 150Rs.

Complete step-by-step answer:
This question can be easily solved using unitary method.
It is given that the sales tax on purchase of Rs. 60 is = Rs. 4.20.
By dividing both sides by 60, we get:
 The sales tax on a purchase of Rs. 1 would be = $\dfrac{{4.2}}{{60}} = \dfrac{{42}}{{600}} = \dfrac{7}{{100}}$Rs.
Multiplying both the sides by 150, we get:
The sales tax on a purchase of Rs. 150 would be = $\dfrac{7}{{100}} \times 150 = 7 \times \dfrac{{150}}{{100}}$
$
   = 7 \times 1.5 \\
   = 10.5Rs. \\
 $
Hence, the sales tax on a purchase of Rs. 150 will be Rs.10.5.

Note: This question can also be solved d by the following method:
 The sales tax on a purchase worth Rs 60 is Rs 4.20
This means, if Purchase = Rs 60
 Then, Sale Tax = 4.2 Rs
$ \Rightarrow $Sale Tax % $ = \dfrac{{4.2}}{{60}} \times 100 = \dfrac{{420}}{{60}} = 7\% $
So, if sales tax on a purchase worth Rs 150 has to be found then:
Taking, Purchase = Rs 150 and Sale tax = 7 %
Sale Tax =
$
  7\% {\text{ of 150}} \\
   = \dfrac{7}{{100}} \times 150 \\
   = 7 \times 1.5 \\
 $
= 10.5 Rs