Q) The age of the father is twice the sum of the ages of his two children. After 20 years, his age will be equal to the sum of the ages of his children. Find the present age of the father. Ans: Let’s consider Father’ age be X and children’s age be Y and Z […]
pair of linear equations
Q) In a 2-digit number, the digit at the unit’s place is 5 less than the digit at the ten’s place. The product of the digits is 36. Find the number. Ans: Let’s consider X is the digit at unit’s place and Y is the digit at ten’s place. The number will be 10 Y +
In a 2-digit number, the digit at the unit’s place is 5 less than the digit Read More »
Q) Tara scored 40 marks in a test, getting 3 marks for each right answer and losing 1 mark for each wrong answer. Had 4 marks been awarded for each correct answer and 2 marks been deducted for each wrong answer, then Tara would have scored 50 marks. Assuming that Tara attempted all questions, find
Tara scored 40 marks in a test, getting 3 marks for each right answer and losing Read More »
Q) The sum of the digits of a 2-digit number is 14. The number obtained by interchanging its digits exceeds the given number by 18. Find the number. Ans: Let’s consider X and Y are the digits of the given number. Hence the given number is 10 X + Y ∴ the sum of the digits
Q) Solve the following system of linear equations : 2 x + 5 y = – 4 and 4 x – 3 y = 5 Ans: Given equations are: 2 x + 5 y = – 4 …………………… (i) 4 x – 3 y = 5 …………………..(ii) To get the value of variables, we need to
Solve the following system of linear equations : 2 x + 5 y = – 4 and 4 x – 3 y = 5 Read More »
Q) Solve the following system of linear equations : 7 x – 2 y = 5 and 8 x + 7 y = 15 and verify your answer. Ans: Given equations are: 7 x – 2 y = 5 …………………… (i) 8 x + 7 y = 15 …………………..(ii) To get the value of variables,
Q) Solve the following system of linear equations : 2p + 3q = 13 and 5p – 4q = – 2 Ans: Given equations are: 2p + 3q = 13 …… ………….. (i) and 5p – 4q = – 2 …………… (ii) To get the value of variables, we need to drop one variable. Let’s
Solve the following system of linear equations : 2p + 3q = 13 Read More »
Q) In a chemistry lab, there is some quantity of 50% acid solution and some quantity of 25% acid solution. How much of each should be mixed to make 10 litres of 40% acid solution? Ans: Let consider quantity of 50% acid solution be V litres ∵ total quantity of final solution is 10 litres ∴
In a chemistry lab, there is some quantity of 50% acid solution and some quantity of 25% Read More »
Q) The monthly incomes of A and B are in the ratio 8 : 7 and their expenditures are in the ratio 19 : 16. If each saves 2500 per month, find the monthly income of each. Ans: Let the income of A and B be 8 X and 7 X Since Saving = Income
Q) Solve the following pair of linear equations: Ans: Given the equations: ……….. (i) ………….(ii) Step 1: Let’s multiply equation (i) by b2 and add to equation (ii), we get: ……….. (i) ∴ ……….. (i) ∴ ……….. (i) ∴ b2 x + a2 x = a ( a2 + b2 ) ∴ x (a2 + b2
Solve the following pair of linear equations: x/a – y/b =0, a x + b y = a2 + b2 Read More »