Quant Question Of The Day: 265
Numbers
For how many positive integers p, is (30 – p)/(p-10) is a prime number ?
For how many positive integers p, is (30 – p)/(p-10) is a prime number ?
(30 – p)/(p-10) = [20 – ( P – 10)]/(p-10) = 20/(p-10) – 1
All the factors of 20 can be possible values of (p-10). In other words, the possible values of 20/(p-10) will be the factors of 20.
Possible values of 20/(p-10) – 1 will be 0, 1, 3, 4, 9 and 19 out of these there are 2 prime numbers.
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good information
By Những dòng bồn cầu thông minh ... , 1 month ago
1 value ( p = 20 )
2 values -11 and 15
2 values; p=11,15