25 because 9x5=45 so 5x5=25
Answer:
Step-by-step explanation:
<u>Mean of four numbers a, b, c, and d is 8:</u>
- (a + b + c + d)/4 = 8
- ⇒ a + b + c + d = 32
<u>Mean of seven numbers x, y, z, a, b, c and d is 12:</u>
- (x + y + z + a + b + c + d)/7 = 12
<u>Substitute the sum of 4 numbers:</u>
- x + y + z + 32 = 7*12
- x + y + z = 84 - 32
- x + y + z = 52
<u>Mean of x, y and z is:</u>
2/3y = 18
y = 18 / (2/3)
y = 18 * 3/2
y = 54/2
y = 27 <==
Answer:
x=w-z
add x to both sides w=z+x
subtract z from both sides w-z=x