Question

Three brands A, B and C of biscuits are available in packets of 12, 15 and 21
biscuits respectively. If a shopkeeper wants to buy an equal number of biscuits of
each brand, what is the minimum number of packets of each brand he should
buy?

Answer 1

LCM of 12 = 2 * 2 * 3

LCM of 15 = 3 * 5

LCM of 21 = 3 * 7


LCM of 12,15,21 = 2 * 2 * 3 * 5 * 7 

                         = 420

Minimum number of packets of A = 420/12 = 35

Minimum Number of packets of B = 420/15 = 28

Minimum Number of packets of C = 420/21 =  20


Hope this helps!

Answer 2

Answer:

We are given that Three brands A, B and C of biscuits are available in packets of 12, 15 and 21  biscuits respectively.

We are supposed to find If a shopkeeper wants to buy an equal number of biscuits of  each brand, what is the minimum number of packets of each brand he should  buy

Find LCM of 12 , 15 , 21

2 | 12            3 | 15           3 | 21

2 | 6             5 |  5            7 | 7

3 |  3               | 1                  | 1

  | 1

12 =$2 \times 2 \times  3$

15 = $3 \times 5$

21 = $3 \times 7$

LCM of 12,15,21 = $2 \times 2  \times 3  \times 5 \times 7$

                          = 420

Minimum number of packets of A = $\frac{420}{12}$ = 35

Minimum Number of packets of B = $\frac{420}{15}$= 28

Minimum Number of packets of C = $\frac{420}{21}$=  20