Linear Equations in One Variable

A boy was asked to multiply a certain number
by 25. He multiplied it by 52 and got his answer more than the correct by 324. The number to be multiplied was

In an examination a student scores 4 marks
for every correct answer and losses 1 mark for every wrong answer. If he attempts 75 questions and scored 125 marks, then the number of questions he attempts correct is

A worker may claim Rs. 15 for each km which
he travels by taxi and Rs. 5 for each km which
he drives his own car. If in one week he claimed Rs. 500 for travelling 80 km, then how
many km did he travel by taxi ?

A class starts at 10 a.m. and lasts at 1 : 27 p.m.
Four periods are held during this interval. After every period, 5 minutes are given free to the students and last period is over exactly at
1 : 27 p.m. The exact duration of each period is

A father is twice as old as his son. 20 years
ago, the age of father was 12 times the age of
his son. The present age of father (in years) is

Rachit is four times as old as his son. Four
years hence the sum of their ages will be 43 years. The present age of the son is