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

Number of biscuits of brand A that can be bought will be a multiple of 12


Number of biscuits of brand B that can be bought will be a multiple of 15


Number of biscuits of brand C that can be bought will be a multiple of 21


Since, shopkeeper wants to buy an equal number of biscuits of each brand


That number should be divisible by 12, 15, 21


Least such number = LCM of 12, 15, 20 = 420


Hence, minimum number of biscuits of each brand shopkeeper has to buy = 420


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