21. The greatest possible length which can be used to measure exactly the lengths 7 m, 3 m 85 cm, 12 m 95 cm is:

A. 15 cm
B. 25 cm
C. 35 cm
D. 42 cm

22. Three numbers which are co-prime to each other are such that the product of the first two is 551 and that of the last two is 1073. The sum of the three numbers is:

A. 75
B. 81
C. 85
D. 89

23. Find the highest common factor of 36 and 84.

A. 4
B. 6
C. 12
D. 18

24. Which of the following fraction is the largest?

25. The least number, which when divided by 12, 15, 20 and 54 leaves in each case a remainder of 8 is:

A. 504
B. 536
C. 544
D. 548