3 and 5 are the correct choices. as long as the 2 lines have different slopes they intersect at only one point
Answer:

the rate of change of height when the water is 1 meter deep is 21 m/min
Step-by-step explanation:
First we need to find the volume of the trough given its dimensions and shape: (it has a prism shape so we can directly use that formula OR we can multiply the area of its triangular face with the length of the trough)

here L is a constant since that won't change as the water is being filled in the trough, however 'b' and 'h' will be changing. The equation has two independent variables and we need to convert this equation so it is only dependent on 'h' (the height of the water).
As its an isosceles triangle we can find a relationship between b and h. the ratio between the b and h will be always be the same:

this can be substituted back in the volume equation

the rate of the water flowing in is:

The question is asking for the rate of change of height (m/min) hence that can be denoted as: 
Using the chainrule:

the only thing missing in this equation is dh/dV which can be easily obtained by differentiating the volume equation with respect to h


reciprocating

plugging everything in the chain rule equation:



L = 12, and h = 1 (when the water is 1m deep)


the rate of change of height when the water is 1 meter deep is 21 m/min
Answer: price of the watch before the discount is £23.5825
Step-by-step explanation:
Let x represent the original price of the watch.
Jason went shopping he bought a watch and a pair of trainers for a total price of £53.55. This price includes 15% loyalty discount. The value of the discount is
15/100 × 53.55 = 8.0325
This means that the original cost of both items is
53.55 + 8.0325 = 61.5825
Before the discounts, the trainers were priced at £38. Therefore,
38 + x = 61.5825
x = 61.5825 - 38
x = 23.5825
Answer:
if it's true simple interest then each year's interest is the same so interest for one year is a quarter of 241.50 which give you the rate but if each year's interest in left in the account the result will be different , it is a really poorly worded question