In a group of 36 pupils, 10 play the flute only. 15 play the piano only. 4 play neither instrument. A student is selected at random. What is the probability the student plays both instruments?

9

Step-by-step explanation:

First you would need to subtract all the irrelevant students.

So, subtract 4 from 36, which is 34.

34 - (10 + 15) =

34 - 25 =

9

The answer is 9 pupils.

-10i^2-4i

step-by-step explanation:

evaluate for p=2,q=5i

(2−4)(2+5i)i

(2−4)(2+5i)i

=−10i2−4i

x = -3

y = -18

step-by-step explanation:

to solve by substitution, substitute one variable and solve for the other. then substitute again to find the remaining variable.

x-1/3(3x-9) = -3 since y=3x-9 substittute y.

x-1/3(3x-9)=-3

x + x +3 = -3

2x+3=-3

2x+3-3= -3-3

2x=-6

x=-3

substitute again into y=3x-9

y=3(-3)-9

y=-9-9

y=-18