She worked as a carpenter for 12 hours and as a blacksmith for 18 hours.
Assuming you mean she earned $20 as a carpenter and $25 as a blacksmith per hour, with a total of 30 hours for $690,
let c represent carpenter hours and b for blacksmith hours.
20c + 25b = 690
c + b = 30
Subtract b from each side so that c = 30 - b
Plug this value into the first equation
20(30 - b) + 25b = 690
600 - 20b + 25b = 690
600 + 5b = 690
5b = 90
b = 18
To find c, plug this value of b into the other equation
c + 18 = 30
c = 12
The answer is 4/6 which can be reduced to 2/3.
Answer:
chicken and chicken
Step-by-step explanation:
just took the test
It is B because 40x32=1280 and 5x4=20 then divide 1280 by 20 and you get 64 but you can’t have 64 so you would need to only have 60 so the answer is B
9514 1404 393
Answer:
21.25 seconds
Step-by-step explanation:
In miles per second, the speed of the jet is ...
(720 mi/h)/(3600 s/h) = 1/5 mi/s
The speed of the sound is the same:
(1 mi)/(5 s) = 1/5 mi/s
Then the rate of closure between the airplane and the sound is ...
(1/5 mi/s) +(1/5 mi/s) = 2/5 mi/s
To find the time required to close a gap of 8 1/2 miles, we can use the relation ...
time = distance/speed
time = (8.5 mi)/(0.4 mi/s) = 21.25 s
The pilot will hear the thunder 21.25 seconds after the flash.
