Question

The LCM of 54 90 and a third number is 1890 and their HCF is 18 The third number is

• A. 36
• B. 180
• C. 126
• D. 108

Answer 1

Answer: (C)

126

Given the LCM two numbers 54, 90 and third number is 1890 and HCF is 18

Let the number is 18x because one factor is also 18 the common factor HCF

Then factor 54,90 ,18 =$18\times 3,18\times 5,18\times 18\times x$

$\therefore 18\times 3\times 5\times x=1890\Rightarrow 270x=1890\Rightarrow x=7$

Then third number is $18\times 7=126$