Answer:
8/3
Step-by-step explanation:
i put equations as this:
x+40 = y
where x is galllons of pure mixture and y is the gallons of the new mixture
the other equation i id was:
x+0.2(40) = 0.25y
x+8 = 0.25y
y = 4x+32
solve using substitution
(x+40) = 4x+32
x = 4x-8
-3x = -8
x = 8/3
Answer:
7/20 = x/400
Step-by-step explanation:
The error is in the second step they subtracted 3 from both sides but it was a 3x, which you can not do.
Correction.
9x+18+3x=1
12x+18=1
12x=-17
x=-17/12
Answer:
A. 
Step-by-step explanation:
We want to find the Z-score of
if the population mean is
,and the population standard deviation is
.
We use the formula:

We substitute the values to obtain:



The correct answer is A.
Answer: 27
Step-by-step explanation:
The given sequence : 13, 24, 35, ....
Here, first term : a= 13
Common difference: d=24-13 =11
The nth term of arithmetic sequence is given by :-

It is given that the nth term is 299, so put

Subtract 13 from both sides , we get

Divide both sides by 11, we get

Add 1 on both sides , we get

Hence, the value of n= 27