Question
Find the LCM and HCF of the following integer by applying the prime factorisation method.
12, 15 and 21
12, 15 and 21
✓
Answer
12 = 2 × 2 × 3 15 = 5 × 3 21 = 7 × 3 3 is common for all, it means HCF of 12, 15 & 21 is 3 Now calculate LCM of 12, 15, 21$\begin{array}{c|c} 2 & 12-15-21 \\ \hline 2 & 6-15-21\\\hline3 & 3-15-21\\\hline 5 & 1-5-7\\\hline7 & 1-1-7\\\hline & 1-1-1\end{array}$
So LCM of 12, 15, 21 is 2 × 2 × 3 × 5 × 7 = 420 From the above, HCF (12, 15, 21) = 3 and LCM (12, 15, 21) = 420
So LCM of 12, 15, 21 is 2 × 2 × 3 × 5 × 7 = 420 From the above, HCF (12, 15, 21) = 3 and LCM (12, 15, 21) = 420
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
State whether the following are true or false. Justify your answer.
cot A is the product of cot and A.
cot A is the product of cot and A.
Prove that:$\frac{\sin70^\circ}{\cos20^\circ}+\frac{\text{cosec }20^\circ}{\sec70^\circ}-2\cos70^\circ\text{cosec }20^\circ=0$
→Solve the following quadratic equation by factorization.
$7 m^2=21 m$
→$7 m^2=21 m$
A card is drawn at random from a pack of 52 cards. Find the probability that the card drawn is:
A queen.
A queen.
In a circle of radius 6cm, a chord of length 10cm makes an angle of 110° at the centre of the circle. Find:
The area of the circle.
The area of the circle.
In figure 3.76, seg PQ is a diameter of a circle with centre O. R is any point on the circle. seg RS⊥seg PQ.
Prove that, SR is the geometric mean of PS and SQ. [That is, SR² = PS ×SQ]
Prove that, SR is the geometric mean of PS and SQ. [That is, SR² = PS ×SQ]
A square water tank has its side equal to $40 \text {m}$ . There are four semi-circular grassy plots all round it.
Find the cost of turfing the plot at $\text {Rs}.1.25$ per square metre (Take $\pi=3.14$ ).
→Find the cost of turfing the plot at $\text {Rs}.1.25$ per square metre (Take $\pi=3.14$ ).
It is known that a box of $200$ electric bulbs contains $16$ defective bulbs. One bulb is taken out at random from the box. What is the probability that the bulb drawn is:
→-
Defective.
-
Nondefective.
Arati Gas Agency supplied LPG cylinder to the consumer for taxable value of ` 545. GST charged is 5%. What is the amount of CGST and SGST in the tax invoice ? What is the total amount paid by the consumer ? Find the amount of GST to be paid by Arati Gas Agency.