Answer:
Bobby around 131 minutes and Billy around 111 minutes
Step-by-step explanation:
To solve the problem it is important to raise equations regarding what happens.
They tell us that Billy (Bi) and Bobby (Bo) can mow the lawn in 60 minutes. That is to say that what they prune in a minute is giving as follows:
1 / Bo + 1 / Bi = 1/60 (1)
They say Billy could mow the lawn only in 20 minutes less than it would take Bobby, therefore
1 / Bi = 1 / (Bo-20) (2)
Replacing (2) in (1) we have:
1 / Bo + 1 / (Bo-20) = 1/60
Resolving
(Bo - 20 + B0) / (Bo * (Bo-20) = 1/60
120 * Bo - 1200 = Bo ^ 2 - 20Bo
Rearranging:
Bo ^ 2 - 140Bo -1200 = 0
Now applying the general equation
Bo = 130.82 or Bo = 9.17, <em>this last value cannot be because Billy took 20 minutes less and neither can he prune faster than the two together</em>, therefore Bobby only takes around 131 minutes and Billy around 111 minutes
Checking with equation 1:
1/131 +1/111 = ~ 1/60
Answer: 681 square inch
Step-by-step explanation:
Hi, we have to apply the formula for the surface area:
A = 2wl + 2lh + 2hw
Where:
w: width
l: length
h: height
Replacing with the values given:
A = (2x12x18.25) + (2x12x3)+(2x18.25x3)
A= 438+72+109.25
A=619.5 in2
Since it has to be 10% more than the surface.
619.5 x (10/100) = 61.95 in2
Adding that value to the surface area
619.5+61.95 = 681.45in2 = 681 in2
2x 2 is the answer your looking for,
When there are two variables (letters) you combine them by adding
8.5
the tenth is the first digit behind the dot. 4 rounds down so the 5 stays a 5
Answer:
I would go with the second one.
Step-by-step explanation:
