Answer:
See below ~
Step-by-step explanation:
<u>Given</u>
- Maitri and Aabhas do a work in 12 hours
- Aabhas and Kavya do the work in 15 hours
- Kavya and Maitri do the work in 20 hours
<u>Solving</u>
- Take Maitri, Aabhas, and Kavya to be x, y, z respectively
- <u>x + y = 12</u> (1)
- <u>y + z = 15</u> (2)
- <u>x + z = 20</u> (3)
<u>Take Equation 1 and rewrite it so that it is equal to x.</u>
<u>Take Equation 2 and rewrite it so that it is equal to z.</u>
<u>Now, substitute these values in Equation 3.</u>
- x + z = 20
- 12 - y + 15 - y = 20
- -2y + 27 = 20
- 2y = 7
- y = 7/2 = <u>3.5 hours [Aabhas]</u>
<u></u>
<u>Substitute the value of y in Equation 1.</u>
- x + 3.5 = 12
- x = <u>8.5 hours [Maitri]</u>
<u>Substitute the value of y in Equation 2.</u>
- 3.5 + z = 15
- z = <u>11.5 hours [Kavya]</u>
<u></u>
<u>Add the values of x, y, and z together.</u>
- x + y + z
- 8.5 + 3.5 + 11.5
- 12 + 11.5
- <u>23.5 hours [together]</u>
Take 1960 as 0 then find out next year's
- 1970=10
- 1980=20
- 1990=30
- 2000=40
- 2005=45
- 2010=50
Also
Divide each population by one thousand i.e turn to decimal .
This we done to create the plot on graph easily
The graph has been attached
for the below points
- (0,9.706)
- (10,10.652)
- (20,10.798)
- (30,10.847)
- (40,11.353)
- (45,11.478)
- (50,11.576)
Sec is 1/cos so sec -120 is 1/cos -120 which is -2