The answer for this question is C.
Answer:
Barbara's speed in clear weather is 
and in the thunderstorm is 
.
Step-by-step explanation:
Let 
be the speed and 
be the time Barbara drives in clear weather, and let 
be the speed and 
be the time she drives in the thunderstorm.
Barbara drives 22 mph lower in the thunderstorm than in the clear weather; therefore,
(1). 
Also,
(2). 
(3). 
,
and
(4). 
From equations (2) and (3) we get:
putting these in equation (4) we get:
and substituting for from equation (1) we get:
This equation can be rewritten as
which has solutions
We take the first solution 
because it gives a positive value for 
.
Thus, Barbara's speed in clear weather is and in the thunderstorm is .
Answer:
Step-by-step explanation:
I have 30 coins, all nickels, dimes, and quarters, worth $4.60. There are two more dimes than quarters. How many of each kind of coin do I have.
..
let quarters be x
dimes = x+2
...
dimes + quarters = x+x+2=2x+2
...
nickels = 30-(2x+2)
...
5(30-(2x+2))+10(x+2)+25x=460
5(30-2x-2)+10x+20+25x=460
150-10x-10+10x+20+25x=460
160+25x=460
-160
25x=460-160
25x=300
/25
x=300/25
x=12 ---- quarters
x+2= 12+2=14 dimes
30-(2x+2)=4 nickels
...
check
4*5+14*10+12*25=20+140+300=460
I don’t think he did distributive property
