Math Destroyer, explain please

[deeentist79]

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can any one help me out with this rate question.
Two work crews, Crew A and crew B starts digging a 300 feet tunnel. Crew A digs 12 feet per day, while crew B digs 18 feet a day. How many feet will Crew A have dug when the two crew meets?

The answer is 180 Feet, and my question is why is it 180 feet and not 120 feet??😕

 

[ToBeDDSS]

The answer is 120 ft

 

[Papasmurf1234]

The answer is 120 ft

I second that.

 

[smilebig01]

i got 180..how did you guys get 120? am i doing something wrong lol

is 180 the answer in destroyer?

 

[Papasmurf1234]

i got 180..how did you guys get 120? am i doing something wrong lol

is 180 the answer in destroyer?

I did it manually since i'm lazy lol.

Group A digs 12 ft/day and Group B digs 18 ft/day.

You have to assume they're digging on opposite ends since they'll meet eventually.

After 10 days, Group A digs 120 ft and Group B digs 180 ft.
In total that's 300 ft.

 

[deeentist79]

Destroyer lists the answer as 180 feet ,i got 120 feet, thats why i dont get why it is 180 feet and not 120.

 

[Papasmurf1234]

Destroyer lists the answer as 180 feet ,i got 120 feet, thats why i dont get why it is 180 feet and not 120.

They probably mistakenly put Group A in the question rather than finding how many feet for Group B.

 

[ToBeDDSS]

The combined rate for both crews is 30ft/day. Therefore it will take them 10 days to dig the tunnel. Which means that crew A has dug : 12x10 = 120 ft.

 

[chanberg]

12x+18x = 30x
30x = 300
x=10
12(10) = 120 ft