In this blog, we will discuss 6 questions that are likely to be asked in GATE 2021. The topics which are covered in this blog are Problems on ages, compound interest, simple interest and algebra.

### In 2002, Badhul’s age was one third age of Rishabh. In 2010 Badhul’s age was half the age of Rishabh. What is Badhul’s year of birth?

#### solution

In 2002, Badhul’s age is one third age of Rishabh so, B = R/3 or R = 3B

In 2010, B+8 = (R+8)/2

2(B+8) = 3B + 8

2B + 16 = 3B + 8

B = 8

R = 3B = 24

The year of birth of Badhul is 1994

### Govind Purchases 3 Bulbs, 7 Sockets, and 1 Fan and pays Rs. 1200 on the first day. The next day, he purchases 4 Bulbs, 10 sockets, and 1 Fan from the same shop and pays Rs. 1645. Then how much he had to pay if he purchases 1 Bulb, 1 Socket and 1 Fan on the third day from the same shop and prices remained unchanged?

#### Solution

[3B+ 7S + 1F = 1200]….(1)

[4B + 10S + 1F = 1645] ….(2)

subtract equation 1 and 2 then you will get,

-B – 3S = -445

B + 3S = 445

4B + 10S + 1F = 3B + 9S + (1B + 1S +1F) = 1645

1645 = 3[B + 35] + ( 1B + 1S + 1F)

1645 = 3 x 445 + (1B + 1S + 1F)

1B + 1S + 1F = 310 Ans