Which of the following groups of fractions is in descending order?

Which of the following groups of fractions is in descending order?

A. 8/15, 9/13, 6/11
B. 8/15, 6/11, 9/13
C. 9/13, 6/11, 8/15
D. 6/11, 8/15, 9/13
Explanation:
The fractions considered are 8/15 9/13 6/11
To compare them we make the denominators the same. So the fractions are
(8 * 13 * 11)/2145, (9 * 15 * 11)/2145 and (6 * 15 * 13)/2145
1144/2145, 1485/2145 and 1170/2145
so in descending order the fractions will be
1485/2145, 1170/2145 and 1144/2145 i.e., 9/13 , 6/11 , 8/15

The value of (2.75)3 – (2.00)3 – (0.75)3 is__________?

The value of (2.75)3 – (2.00)3 – (0.75)3 is__________?

A. 3 * 2.75 * 2.75 * 2.75
B. 3 * 2.00 * 2.00 * 2.00
C. 3 * 2.75 * 0.75 * 2.75
D. 4.5 * 2.75
Explanation:
(2.75)3 – (2.00)3 – (0.75)3
a3 + b3 + c3 = (a + b + c)(a3 + b3 + c3 – ab – bc – ca)
If a + b + c = 0 then a3 + b3 + c3 = 3abc
Hence 2.75 – 2.00 – 0.75 = 0
So, (2.75)3 – (2.00)3 – (0.75)3
= 3 * 2.75 * 2 * 0.75 = 3 * 1.5 * 2.75
= 4.5 * 2.75