A : C = 100 : 87.
B | = | B | x | A | = | 90 | x | 100 | = | 30 | . |
C | A | C | 100 | 87 | 29 |
When B runs 30 m, C runs 29 m.
When B runs 180 m, C runs | ❨ | 29 | x 180 | ❩m | = 174 m. |
30 |
∴ B beats C by (180 - 174) m = 6 m.
A : C = 60 : 40.
∴ | B | = | ❨ | B | x | A | ❩ | = | ❨ | 45 | x | 60 | ❩ | = | 45 | = | 90 | = 90 : 80. |
C | A | C | 60 | 40 | 40 | 80 |
∴ B can give C 10 points in a game of 90.
A's speed = | ❨ | 5 x | 5 | ❩m/sec | = | 25 | m/sec. |
18 | 18 |
Time taken by A to cover 100 m = | ❨ | 100 x | 18 | ❩sec | = 72 sec. |
25 |
∴ Time taken by B to cover 92 m = (72 + 8) = 80 sec.
∴ B's speed = | ❨ | 92 | x | 18 | ❩kmph | = 4.14 kmph. |
80 | 5 |
While A covers 3 m, B covers 4 m.
While A covers 360 m, B covers | ❨ | 4 | x 360 | ❩m | = 480 m. |
3 |
Thus, when A reaches the winning post, B covers 480 m and therefore remains 20 m behind.
∴ A wins by 20 m.
B : C = 100 : 96.
∴ A : C = | ❨ | A | x | B | ❩ | = | ❨ | 100 | x | 100 | ❩ | = | 100 | = 100 : 72. |
B | C | 75 | 96 | 72 |
∴ A beats C by (100 - 72) m = 28 m.
7 | 4 | m |
7 |
A : C = 200 : 182.
C | = | ❨ | C | x | A | ❩ | = | ❨ | 182 | x | 200 | ❩ | = 182 : 169. |
B | A | B | 200 | 169 |
When C covers 182 m, B covers 169 m.
When C covers 350 m, B covers | ❨ | 169 | x 350 | ❩m | = 325 m. |
182 |
Therefore, C beats B by (350 - 325) m = 25 m.
Ratio of the speeds of A and B = | 5 | : 1 = 5 : 3. |
3 |
Thus, in race of 5 m, A gains 2 m over B.
2 m are gained by A in a race of 5 m.
80 m will be gained by A in race of | ❨ | 5 | x 80 | ❩m | = 200 m. |
2 |
∴ Winning post is 200 m away from the starting point.
A : C = 100 : 72.
∴ | B | = | ❨ | B | x | A | ❩ | = | ❨ | 80 | x | 100 | ❩ | = | 10 | = | 100 | = 100 : 90. |
C | A | C | 100 | 72 | 9 | 90 |
∴ B can give C 10 points.
Distance covered by B in 9 sec. = | ❨ | 100 | x 9 | ❩m | = 20 m. |
45 |
∴ A beats B by 20 metres.
1 |
22 |
3 |
22 |
2 |
91 |
2 |
77 |
2 |
91 |
Then, n(S) | = number of ways of drawing 3 balls out of 15 | |||
= 15C3 | ||||
|
||||
= 455. |
Let E = event of getting all the 3 red balls.
∴ n(E) = 5C3 = 5C2 = | (5 x 4) | = 10. |
(2 x 1) |
∴ P(E) = | n(E) | = | 10 | = | 2 | . |
n(S) | 455 | 91 |
1 |
2 |
2 |
5 |
8 |
15 |
9 |
20 |
9 |
20 |
Let E = event of getting a multiple of 3 or 5 = {3, 6 , 9, 12, 15, 18, 5, 10, 20}.
∴ P(E) = | n(E) | = | 9 | . |
n(S) | 20 |
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