Q) A 2-digit number is such that the product of its digits is 18. When 63 is subtracted from the number, the digits interchange their places. Find the number. Ans: Step 1: Let’s consider X and Y are the digits of the given number. Hence the given number is 10 X + Y ∴ the […]
A 2-digit number is such that the product of its digits is 18. When 63 is subtracted Read More »
Q) Three bells ring at intervals of 9, 12 and 15 minutes respectively. If they start tolling together, after what time will they next toll together? Ans: STEP-BY-STEP SOLUTION The three bells will ring together again when the time gap is perfect multiple of each bell’s interval Therefore, we will take LCM of three time
Q) The H.C.F of 85 and 238 is expressible in the form 85m -238. Find the value of m. Ans: By prime factorisation, we solve 85 and 238 one by one: 85 = 5 x 17 238 = 2 x 7 x 17 Hence the HCF of these two numbers = 17 Since it is
The H.C.F of 85 and 238 is expressible in the form 85m -238. Find the value of m. Read More »
Q) Find the H.C.F and L.C.M of 480 and 720 using the Prime factorisation method. Ans: VIDEO SOLUTION STEP BY STEP SOLUTION Step 1: By prime factorisation, we solve 480 and 720 one by one: ∴ 480 = 2 x 2 x 2 x 2 x 2 x 3 x 5 = 25 x 3
Find the H.C.F and L.C.M of 480 and 720 using the Prime factorisation method. Read More »
Q) The sum of two numbers is 18 and the sum of their reciprocals is 9/40. Find the numbers. Ans: Let the numbers be X and Y Step 1: By first condition: X + Y = 18 ………… (i) Step 2: By second condition: ∴ ∴ 40 (Y + X) = 9 X Y e
The sum of two numbers is 18 and the sum of their reciprocals is 9/40. Find the numbers. Read More »
Q) Sum of two numbers is 105 and their difference is 45. Find the numbers. Ans: Let the numbers be X and Y Step 1: By first condition: X + Y = 105 ………… (i) By second condition: X – Y = 45 ………. (ii) Step 2: By adding these two equations, we get: (X
Sum of two numbers is 105 and their difference is 45. Find the numbers. Read More »
Q) The denominator of a fraction is one more than twice the numerator. If the sum of the fraction and its reciprocal is 2 16/21, find the fraction. Ans: Let the Numerator be A, then by given 1st condition, denominator = 2 A + 1 Hence the fraction is: And its reciprocal will be: By
The denominator of a fraction is one more than twice the numerator. If the sum of the Read More »
Q)Teaching Mathematics through activities is a powerful approach that enhances students’ understanding and engagement. Keeping this in mind, Ms. Mukta planned a prime number game for class 5 students. She announces the number 2 in her class and asked the first student to multiply it by a prime number and then pass it to second
Teaching Mathematics through activities is a powerful approach that enhances students’ Read More »
Q) Can the number (8n), n being a natural number, end with the digit 0 ? Ans: For any number to end with the digit 0, it will be divisible by 10 Since 10 = 2 x 5, therefore, a number ending with digit 0 will be divisible by 2 and 5 both. Next, since
Can the number (8n), n being a natural number, end with the digit 0? Give reasons. Read More »
Q) Explain why 7 × 11 × 13 + 13 and 7 × 6 × 5 × 4 × 3 × 2 × 1 + 5 are composite numbers. Ans: Let’s take both numbers one by one and analyse: (i) 7 × 11 × 13 + 13 = 13 (7 x 11 + 1) = 13
Explain why 7 × 11 × 13 + 13 and 7 × 6 × 5 × 4 × 3 × 2 × 1 + 5 are composite numbers. Read More »