Question 8 A water tank initially contained 51 liters of water. It is then drained at a constant rate of 2.5 liters per minute.
1 answer:
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Answer:
see explanation
Step-by-step explanation:
a
The tangent and the radius at the point of contact form a right angle
Using Pythagoras' identity on the right triangle formed.
Let x be the distance from the centre to P, then
x² = 4² + 10² = 16 + 100 = 116 ( take the square root of both sides )
x = ≈ 10.77 cm (to 2 dec. places )
b
let the required angle be Θ, then
Using the sine or cosine ratio in the right triangle.
cosΘ = =
Θ = (
) ≈ 21.8°
You must drive more than 40 miles to make option A the cheaper plan
<em><u>Solution:</u></em>
Two payment options to rent a car
Let "x" be the number of miles driven in one day
<em><u>You can pay $20 a day plus 25¢ a mile (Option A)</u></em>
25 cents is equal to 0.25 dollars
OPTION A : 20 + 0.25x
<em><u>You pay $10 a day plus 50¢ a mile (Option B)</u></em>
50 cents equal to 0.50 dollars
Option B: 10 + 0.50x
<em><u>For what amount of daily miles will option A be the cheaper plan ?</u></em>
For option A to be cheaper, Option A must be less than option B
Option A < Option B
Solve the inequality
Add -0.50x on both sides
Add - 20 on both sides,
Divide both sides by 0.25
Thus you must drive more than 40 miles to make option A the cheaper plan