3x = 4y
X+y = 21
Multiply second equation by 3
3x+3y= 63
Substitute 3x with 4y
4y + y = 21
5y = 21
Y=4.2
X + 4.2 = 21
x= 16.8
Answer:
Step-by-step explanation:
Sally Jonas worked hours is
Monday - 8hours
Tuesday - 7hours
Wednesday - 8hours
Thursday - 10hours
Friday - 8hours
Total work hour = 8 + 7 + 8 + 10 + 8
Total work hour = 41 hours
Rate of pay = $4.95 / hour
So, the total pay for a week is
Total pay = total work hour × pay rate
Total pay = 41 × 4.95
Total pay =$202.95
Step-by-step explanation:
Take John's sister's age as "x"
So, so twice his sister's age means = 2x
And 5 years more, means = 2x + 5
So finally John's age = 2x + 5
Compare both sides,
x² - x - 1 = 2 - 3x
x² + 2x - 3 = 0
x² -x + 3x - 3 = 0
x(x - 1) 3(x - 1) = 0
(x - 1)(x+3) = 0
x = 1 or - 3
In short, Your Answers would be 1 & -3
Hope this helps!
Answer:
7
Step-by-step explanation:
σ = 4 ; μ =?
8.52 to the left of X
.
P(X < 8.52) = 64.8%
P(X < 8.52) = 0.648
Using the Z relation :
(x - μ) / σ
P(Z < (8.52 - μ) / 4)) = 0.648
The Z value of 0.648 of the lower tail is equal to 0.38 (Z probability calculator)
Z = 8.52 - μ / 4
0.38 = 8.52 - μ / 4
0.38 * 4 = 8.52 - μ
1.52 = 8.52 - μ
μ = 8.52 - 1.52
μ = 7