maths help please

1)
A submarine stays at 150 m below water surface. It first ascends vertically to a position of 42 m below water surface and then descends vertically to a position of 135 m below the water surface. If -60 denotes 60 m below the water surface, find the total distance travelled by the submarine.

(-42 m) – (-150 m) = 108 m (ascending)
(-135 m) – (-42 m) = -93 m (descending)
Total distance traveled = 108 m + 93m = 201 m

Ignore the sign, since we are concerned with distance travelled. (If you know physics, we are dealing with scalar quantity, not vector quantity like displacement)

2)
Given that the distance between A(-5,-2) and B(x,-2) is 6 units. Are the coordinates of B unique? Briefly explain your answer.

The coordinates of B are not unique because there are two answers for x.
D^2 = (x2 – (x1))^2 + (y2 – y1)^2
6^2 = (x2 – (-5))^2 + (-2 – (-2))^2
36 = (x2 + 5)^2 + (-2 +2)^2
36 = (x2 + 5)^2
(x2 + 5)^2 = 36
x2 + 5 = 6 or -6
x2 = 6 -5 = 1
x2 = -6 -5 = -11

So x can either 1 or -11. The coordinates of B are not unique.

3)
There are k bags of chocolates and each bag has p pieces of chocolates. If 3 pieces of chocolates are eaten, how many pieces of chocolate are there?

Total number of pieces of chocolates in k bags = kp
Number of pieces of chocolates in k bags if 3 pieces are eaten = kp - 3

4)
The profits made by selling a hamburger and a can of soft drinks are $x and $y respectively. If 28 hamburgers and 20 cans of soft drink were sold yesterday, what was the total profit made?

Total profit made = profit from hamburger + profit from soft drinks
Total profit made = $ 28x + $ 20y