Two numbers are in the ratio 3 : 4. If their L.C.M. is 72. what is sum of the numbers?
Choose the correct choice from the following answers.
A) 42
B) 56
C) 76
D) 84
E) 85
Explanation:   Let the numbers be 3x and 4x   LCM of 3x and 4x = 12x (Since LCM of 3 and 4 is 12. Hence LCM of 3x and 4x is 12x)   Given that LCM of 3x and 4x is 72   =&gt; 12x = 72   =&gt; x = 72/12= 
<gadget id="calculator">72/12</gadget>
<output>6</output>
6   Sum of the numbers= 3x + 4x   = 7x   3  + 4= 
<gadget id="calculator">3  + 4</gadget>
<output>7</output>
7x= 7 x 6 = 42   42nswer: Option 42
<result>A</result>
Two numbers are in the ratio 3 : 4. If their L.C.M. is 72. what is sum of the numbers?