Question

solve it rightly plz

Answer 1

$(a) \frac{12 \times 20}{4} = 12 \times 5 = 60 \\ (b) \frac{15 \times 45}{15} = 45$

Answer 2

(a)
Prime factors of 12 = 2×2×3
Prime factors of 20 = 2×2×5
HCF of(12 and 20)= 2×2 =4
LCM of two numbers =(First number × second number)/ HCF
LCM of two numbers =( 12×20)/4=60
(b)
Prime factors of 15 = 3×5
Prime factors of 45 = 3×3×5
HCF of(15 and 45)=3×5 = 15
LCM of two numbers =(First number × second number)/ HCF
LCM of two numbers =(15×45)/15=45