If $3x + 4y = 12$ and $x - y = 1$, what is the value of $x + y$?
24/7
25/4
25/7
23/7
From x − y = 1:
x = y + 1
Substituting x = y + 1 into 3x + 4y = 12:
3(y + 1) + 4y = 12 3y + 3 + 4y = 12 7y + 3 = 12 7y = 9 y = 9/7
Using x = y + 1:
x = (9/7) + 1 = (9/7) + (7/7) = 16/7
Adding the values:
x + y = (16/7) + (9/7) = 25/7
x + y = 25/7
If the probability distribution is given by:
| X | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
|---|---|---|---|---|---|---|---|---|
| P(x) | 0 | k | 2k | 2k | 3k | k² | 2k² | 7k² + k |
Then find: \( P(3 < x \leq 6) \)
If \(S=\{1,2,....,50\}\), two numbers \(\alpha\) and \(\beta\) are selected at random find the probability that product is divisible by 3 :
For any natural number $k$, let $a_k = 3^k$. The smallest natural number $m$ for which \[ (a_1)^1 \times (a_2)^2 \times \dots \times (a_{20})^{20} \;<\; a_{21} \times a_{22} \times \dots \times a_{20+m} \] is: