So it is really easy to solve firstly we can see how much does the first 10 boxes make which makes around 55$ obviously. Secondly 45$ for the next 10 boxes.
So for now we can simply calculate that we have spent around 100$ which means 20 boxes. The remaining money left is 77$ so we can buy 77/3.5 = 22 only 22 boxes with that money. Hence a total of 42 boxes.
Although the question is incomplete, I have seen it before.
The equations are:
3a + 6b = 12
-3a + 6b = -12
Adding the equations, we get:
12b = 0
And b = 0
Answer:
- boat: 6 mph
- current: 2 mph
Step-by-step explanation:
The relationship between time, speed, and distance is ...
speed = distance/time
For boat speed b and current speed c, the speed downstream is ...
b +c = (16 mi)/(2 h) = 8 mi/h
The speed upstream is ...
b -c = (16 mi)/(4 h) = 4 mi/h
Adding the two equations eliminates the c term:
2b = 12 mi/h
b = 6 mi/h . . . . . divide by 2
Solving the second equation for c, we get ...
c = b -4 mi/h = 6 mi/h -4 mi/h = 2 mi/h
The speed of the boat in still water is 6 mi/h; the current is 2 mi/h.
2nd, 4th, and 5th answers are correct
