x*y = .........3 (1) If x and y are integers from 1 to 20, then probability of x and y to s

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05 Dec 2011 probability

x*y = .........3 (1)
If x and y are integers from 1 to 20, then probability of x and y to satisfy the condition (1) will be (In blank space of equation (1) minimum number of integers should be one.

OPtion

1) 1/100
2) 1/200
3) 3/200
4) 3/100
5) 7/100
6) 7/200
7) 11/100
8) 11/200
9) 13/100
10) none of these

Solution

possible set of x and y are (1,13), (3,11), (7,9), (7,19), (9,7), (9,17), (11,3), (11,13), (13,1), (13,11), (17,9), (17,19), (19,7), (19,17)
so probability = 14/400 = 7/200

Correct Option: 6 Best Solution (3)

Dr.Dipin Singh   12 years AGO

total possible combinations are 20*20 = 400

Favourable combinations are
1*13
3*11
13*11
7*9
7*19
17*9
19*17

By changing values of xand y

total possible combinations are 2*7=14

then probability of x and y to satisfy the condition (1) will be (In blank space of equation (1) minimum number of integers should be one = 14/400 = 7/200 ... option 6

Like? Yes (6) | No (1)  

Soni   12 years AGO

probability of x and y to satisfy the condition = 14/400 = 7/200

Like? Yes (2) | No (1)  

susmit   12 years AGO

TOTAL POSSIBILITIES: 20*20 = 400
POSSIBILITIES FOR LAST DIGIT TO BE THREE AND MINIMUM 2 DIGIT NO. ARE:1)1*13 2)11*13 3)11*3
4)7*9 5)17*9 6)7*19 7)17*19 ( REMAINING 7 BY CHANGING THE ORDER OF x AND y.
SO prob=14/400=7/200

Like? Yes (3) | No (2)