The volume of this box is indeed 84 in^3. What were you looking for beyond that?
Base: (7 in)(3 in) = 21 in^2
Height: 4 in
volume = (21 in^2)(4 in) = 84 in^3 (answer)
Simple interest = $769
Principal = $6000
Rate = ?
Time = 10 months (must convert to years if in months) = 10/12 = 0.833
Formula
I = prt
Substitute
769 = 6000 × r × 0.833
769 = 4998r
Divide both sides by 4998
769/4998 = 4998r/4998
0.15386 = r
(to the nearest tenth of a percent) = 0.15
Therefore, your rate is 0.15%.
A + b + c = 168
b = 1/3c
a = b + c....a = 1/3c + c = 4/3c
now we sub
4/3c + 1/3c + c = 168
8/3c = 168
c = 168 * 3/8
c = 504/8
c = 63 <=== Carlos collected 63 lbs
a = 4/3c
a = 4/3(63)
a = 252/3
a = 84 <== Amy collected 84 lbs
b = 1/3c
b = 1/3(63)
b = 63/3 <== Bruce collected 21 lbs
b = 21
Answer is slope of 5
Step by step
You can graph the slope as seen on the attached picture. You go up 30, you go right +6. Slope is y/x, so 30/6, equals 5
You can also use the slope formula
(y2-y1) over (x2-x1)
Using points on the graph
(6,0) and (0,-30)
(-30-0 ) over (0-6)
-30 over -6
-30/-6
= 5