Arithmatical  HCF and LCM of Numberss
11. 
The maximum numbers of students among them 1001 pens and 910 pencils can be distributed in such a way that each student gets the same number of pens and same number of pencils is 

A. 91 
B. 910 

C. 1001 
D. 1911 
Solution 
Required number of students. 
= H.C.F of 1001 and 910. 
‹=› 91. 

Solution 
Clearly, 252 =2 x 2 x 3 x 3 x 7 

13. 
Three different containers contain 496 litres, 403 litres and 713 litres of mixtures of milk and water respectively. What biggest measure can measure all the different quantities exactly? 

A. 1 litre 
B. 7 litre 

C. 31 litre 
D. 41 litre 
Solution 
Required measurement  = H.C.F of (496, 403, 713) litres 
‹=›31 litres. 

14. 
The H.C.F of two numbers is 8. Which one of the following can never be their L.C.M ? 

A. 8 
B. 12 

C. 60 
D. 72 
Solution 
H.C.F of two numbers divides their L.C.M exactly. Clearly, 8 is not a factor of 60. 

15. 
The L.C.M of two numbers is 495 and their H.C.F is 5. If the sum of the numbers is 10, then their difference is 

A. 10 
B. 46 

C. 70 
D. 90 
Solution 
Let the numbers be x and (100  x) . 
Then, x (100  x) = 5 ×495 
‹=›x^{2}  100x + 2475 = 0. 
‹=› (x 55) (x  45) = 0. 
x = 55 or x = 45. 
Therefore, the numbers are 45 and 55. 
Required difference = (55  45) = 10. 
