In a group of 33 pupils, 1 plays the flute only. 12 play the piano only.
10 play neither instrument.
A student is selected at random.
What is the probability the student plays both instruments?

0.303

Step-by-step explanation:

The number of students who plays both flute and Piano can be obtained thus :

Let numbwr who plays both =x

Piano only + flute only + both + neither = total

12 + 1 + x + 10 = 33

23 + x = 33

x = 33 - 23

x = 10

Hence, probability that student plays both instrument :

P = required outcome / Total possible outcomes

P(plays both) = 10 / 33 = 0.303

it is a. 4.2 because 7.6-3.4 gets the remaining length of 4.2. i might be wrong but i am pretty sure this is the answer.

x = ±sqrt(10)

step-by-step explanation:

5 - 2x² = -15

subtract 5 from each side

5-5 - 2x² = -15-5

-2x^2   = -20

divide by -2 on each side

-2x^2   /-2= -20/-2

x^2 =10

take the square root on each side

sqrt(x^2 )=±sqrt(10)

x = ±sqrt(10)

check:

5 - 2x² = -15

+sqrt(10)

5 - 2(sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15

-sqrt(10)

5 - 2(-sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15