Answer:D) 1 hr
Step-by-step explanation:
Given
Pump A and B can fill tank in ![\frac{6}{5} hr](https://tex.z-dn.net/?f=%5Cfrac%7B6%7D%7B5%7D%20hr)
Pump A and C can fill tank in ![\frac{3}{2} hr](https://tex.z-dn.net/?f=%5Cfrac%7B3%7D%7B2%7D%20hr)
Pump B and C can fill tank in ![2 hr](https://tex.z-dn.net/?f=2%20hr)
Let A be the total hr taken A therefore rate of ![A=\frac{1}{A} /hr](https://tex.z-dn.net/?f=A%3D%5Cfrac%7B1%7D%7BA%7D%20%2Fhr)
Let B be the total hr taken B therefore rate of ![B=\frac{1}{B} /hr](https://tex.z-dn.net/?f=B%3D%5Cfrac%7B1%7D%7BB%7D%20%2Fhr)
Let C be the total hr taken C therefore rate of ![C=\frac{1}{C} /hr](https://tex.z-dn.net/?f=C%3D%5Cfrac%7B1%7D%7BC%7D%20%2Fhr)
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Adding 1,2 & 3
![2(\frac{1}{A}+\frac{1}{B}+\frac{1}{C})=\frac{5}{6}+\frac{1}{2}+\frac{2}{3}](https://tex.z-dn.net/?f=2%28%5Cfrac%7B1%7D%7BA%7D%2B%5Cfrac%7B1%7D%7BB%7D%2B%5Cfrac%7B1%7D%7BC%7D%29%3D%5Cfrac%7B5%7D%7B6%7D%2B%5Cfrac%7B1%7D%7B2%7D%2B%5Cfrac%7B2%7D%7B3%7D)
![\frac{1}{A}+\frac{1}{B}+\frac{1}{C}=\frac{2}{2}](https://tex.z-dn.net/?f=%5Cfrac%7B1%7D%7BA%7D%2B%5Cfrac%7B1%7D%7BB%7D%2B%5Cfrac%7B1%7D%7BC%7D%3D%5Cfrac%7B2%7D%7B2%7D)
![\frac{1}{A}+\frac{1}{B}+\frac{1}{C}=1](https://tex.z-dn.net/?f=%5Cfrac%7B1%7D%7BA%7D%2B%5Cfrac%7B1%7D%7BB%7D%2B%5Cfrac%7B1%7D%7BC%7D%3D1)
thus time taken by A,B and C combined is 1 hr
Marcus needs to bike at least 11 miles each day.
Step-by-step explanation:
Given,
Distance to cover = 80 miles at least
Distance already biked = 25 miles
Number of days left = 5
Let,
x be the distance to cover in 5 days.
According to given statement;
Number of days left * Distance to cover + distance already bike ≥ Total distance to travel
![5x+25\geq 80\\5x+25-25\geq 80-25\\5x\geq 55](https://tex.z-dn.net/?f=5x%2B25%5Cgeq%2080%5C%5C5x%2B25-25%5Cgeq%2080-25%5C%5C5x%5Cgeq%2055)
Dividing both sides by 5
![\frac{5x}{5}\geq \frac{55}{5}\\x\geq 11](https://tex.z-dn.net/?f=%5Cfrac%7B5x%7D%7B5%7D%5Cgeq%20%5Cfrac%7B55%7D%7B5%7D%5C%5Cx%5Cgeq%2011)
Marcus needs to bike at least 11 miles each day.
Keywords: inequality, division
Learn more about division at:
#LearnwithBrainly
Answer:
65 years old
Step-by-step explanation:
G . = grandma
d = grand daughter
g = 13d
g+1= 11(d+1) - - distributive property
g + 1 = 11d+11
subtract 1 from both sides
g = 11d+10
substitute g = 13d into equation
13d = 11d+10
subtract 11d from both sides
2d = 10
divide both sides by 2
d = 5. the grandaughter is 5, and the grandma is currently 13 * the granddaughters age. 5*13 = 65. hope it helped