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
Answer: it will take them 48 minutes.
Step-by-step explanation:
John can mow a lawn in 80 minutes. This means that the rate at which he moans the lawn per minute is 1/80
Rocky can mow the same lawn in 120 minutes. This means that the rate at which Rocky can mow the same lawn per minute is 1/120
If they work together, they would work simultaneously and their individual rates are additive. This means that their combined working rate would be
1/80 + 1/120 = 200/9600 = 1/48
Assuming it takes t hours for both of them to clean the room working together, the working rate per hour would be 1/t. Therefore,
1/48 = 1/t
t = 48 minutes
A. -0.3 equals (=) -0.3 so that's false
B. 7/8 is less than (>) 9/10
C. 1 2/3 is less than (<) 1.7
D. -1.2 is less (<) 0.521
Answer:
X = 22
Step-by-step explanation:
f(x) = 3x + 1
f(7) = 3(7) + 1
= 21 + 1
= 22
