39/1.5 = 26 km per hour
51/3 = 17 km per hour
Then you need the mean. 26+17/2 = 21.5 km per hour
Answer:
6
Step-by-step explanation:
Cost per item is found by dividing the cost by the number of items. If the woman bought n items for $120, the cost of each item is $120/n. If the woman bought 24 more items, n+24, at the same price, then the cost per item is $120/(n+24). The problem statement tells us this last cost is $16 less than the first cost:
120/(n+24) = (120/n) -16
Multiplying by n(n+24) gives ...
120n = 120(n+24) -16(n)(n+24)
0 = 120·24 -16n^2 -16·24n . . . . . . subtract 120n and collect terms
n^2 +24n -180 = 0 . . . . . . . . . . . . . divide by -16 to make the numbers smaller
(n +30)(n -6) = 0 . . . . . . . . . . . . . . factor the quadratic
The solutions to this are the values of n that make the factors zero: n = -30, n = 6. The negative value of n has no meaning in this context, so n=6 is the solution to the equation.
The woman bought 6 items.
_____
Check
When the woman bought 6 items for $120, she paid $120/6 = $20 for each of them. If she bought 6+24 = 30 items for the same money, she would pay $120/30 = $4 for each item. That amount, $4, is $16 less than the $20 she paid for each item.
First we distribute
into
and
.
That makes the left side of the equation
Now we subtract
from
, which makes
Now the equation is
Our goal is to isolate
, so we both sides by 30
That will make the equation
We multiply -1 on both sides of the equation:
Finally we simplify
, which makes
So the answer is 
Answer:
There are 3 feet in a yard, so divide 34 by 3, which is 11 with a remainder of 1, the remainder 1 is the remaining foot, so 34 feet is 11 yards and 1 foot.
Step-by-step explanation:
Answer:
The answer here would be 1/6.
Step-by-step explanation:
If Amelia originally has 12 marbles (12/12), then gives away 2, she then has 10 marbles (10/12). This means she gave away 2 of the 12 marbles she has (2/12). This fraction can then be reduced to 1/6 by dividing the denominator and numerator by 2.
