A man rows down a river 15 km in 3 h with the stream and returns in The rate at which he rows in still water is
2.5 km/h
1.5 km/h
3.5 km/h
4.5 km/h
There is 100% increase to an amount in 8 yr, at simple interest. Find the compound interest of ₹ 8000 after 2 yr at the same rate of interest.
₹ 2500
₹ 2000
₹ 2250
₹ 2125
If the number p is 5 more than q and the sum of the squares of p and q is 55, then the product of p and q is
10
-10
15
-15
If a3 - b3 - c3 = 0, then the value of a9 - b9 - c9 - 3a3b3c3 is
1
2
0
-1
C.
0
Given expression,
a3 - b3 - c3 = 0,
⟹ a3 = b3 + c3 ...(i)
On cubing both sides, we get
(a3)3 = (b3 + c3)3
a9 = b9 + c9 + 3b3c3(b3 + c3)
a9 = b9 + c9 + 3b3c3a3
⟹ a9 - b9 - c9 - 3a3b3c3 = 0
A horse is tied to a post by a rope. If the horse moves along a circular path always keeping the rope stretched and describes 88 m when it has traced out 72° at the centre at the length of the rope is
70 m
75 m
80 m
65 m
The value of 152 (sin 30° + 2 cos2 45° + 3 sin 30° + 4 cos2 45° +...+17 sin 30° + 18 cos2 45°) is
an integer but not a perfect square
a rational number but not an integer
a perfect square of an integer
irrational