Answer:
168 minutes
Step-by-step explanation:
It takes 120 minutes for the first person to clean the jellyfish tank.
This means that in 1 minute the first person cleans ![\[\frac{1}{120}\]](https://tex.z-dn.net/?f=%5C%5B%5Cfrac%7B1%7D%7B120%7D%5C%5D%20)
of the tank.
Let the time taken by the second person working alone to clean the tank be x minutes.
Then in 1 minute the second person cleans ![\[\frac{1}{x}\]](https://tex.z-dn.net/?f=%5C%5B%5Cfrac%7B1%7D%7Bx%7D%5C%5D%20)
of the tank.
Working together, the two persons clean,
![\[\frac{1}{120} + \frac{1}{x}\]](https://tex.z-dn.net/?f=%5C%5B%5Cfrac%7B1%7D%7B120%7D%20%2B%20%5Cfrac%7B1%7D%7Bx%7D%5C%5D%20)
of the tank
But it is given that the two persons working together can clean the tank in 70 minutes. This means that in 1 minute both of them can clean ![\[\frac{1}{70}\]](https://tex.z-dn.net/?f=%5C%5B%5Cfrac%7B1%7D%7B70%7D%5C%5D%20)
of the tank.
Expressing in equation form:
![\[\frac{1}{120} + \frac{1}{x} = \frac{1}{70}\]](https://tex.z-dn.net/?f=%5C%5B%5Cfrac%7B1%7D%7B120%7D%20%2B%20%5Cfrac%7B1%7D%7Bx%7D%20%3D%20%5Cfrac%7B1%7D%7B70%7D%5C%5D%20)
![\[=> \frac{1}{x} = \frac{1}{70} - \frac{1}{120} \]](https://tex.z-dn.net/?f=%5C%5B%3D%3E%20%5Cfrac%7B1%7D%7Bx%7D%20%3D%20%5Cfrac%7B1%7D%7B70%7D%20-%20%5Cfrac%7B1%7D%7B120%7D%20%5C%5D%20)
![\[=> \frac{1}{x} = \frac{12-7}{840} \]](https://tex.z-dn.net/?f=%5C%5B%3D%3E%20%5Cfrac%7B1%7D%7Bx%7D%20%3D%20%5Cfrac%7B12-7%7D%7B840%7D%20%5C%5D%20)
![\[=> \frac{1}{x} = \frac{5}{840} \]](https://tex.z-dn.net/?f=%5C%5B%3D%3E%20%5Cfrac%7B1%7D%7Bx%7D%20%3D%20%5Cfrac%7B5%7D%7B840%7D%20%5C%5D%20)
![\[=> \frac{1}{x} = \frac{1}{168} \]](https://tex.z-dn.net/?f=%5C%5B%3D%3E%20%5Cfrac%7B1%7D%7Bx%7D%20%3D%20%5Cfrac%7B1%7D%7B168%7D%20%5C%5D%20)
![\[=> x = 168 \]](https://tex.z-dn.net/?f=%5C%5B%3D%3E%20x%20%3D%20168%20%5C%5D%20)
This means that the second person can clean the tank in 168 minutes.
We have a formula for that( according to the Intersecting chords theorem)
3×4=2×jk
6=jk
When you GRAPH an equation or inequality you plot all of the points that satisfy it.
Answer:27/220
Step-by-step explanation:
She must have 2 �1 coins and 1 50p coin.
She can choose the 2 �1 coins 3C2 = 3 ways.
For each of those 3 ways she can choose the
50p coin 9C1 or 9 ways.
That's 3�9=27 ways to get �2.50.
She can choose any 3 coins in 12C3 = 220 ways.
The desired probability is 27 ways out of
220 ways,or 27/220, or 13.5% of the time.
Answer:
y=10x+99
Step-by-step explanation:
Find the negative reciprocal of the slope of the original line and use the point-slope formula y−y1=m(x−x1) to find the line perpendicular to x+10y=60.
