Question

Solve the following problems completely .

a. Christian can do a job in 6 hours. Requesting Boyet to work with him, the two can do the jon in 4 1/2 hours. How long would it take Boyet to do the job alone?

b. A motorcycle can maintain constant speed of 16 kilometers per hour relative to the water. The boat makes a trip upstream to a certain point is 20 minutes; the return trip take 15 minutes, What is the speed of the current?

c. The perimeter of a rectangle is 28 cm. IF the length were subtracted by2 and the width added by 2, the rectangle would have been a square. What are the dimens

Answer 1

a. 6 + 4 1/2 ÷ 2 = ?

urg I did the other 2 questions earlier this year D: and I forgot how to do them xD

Answer 2

Nooooo D; Upou?

Answer 3

Upou? Idk what that means

Answer 4

Nevermind. T_T but please do remember :<

Answer 5

Give me a sec and I'll see if I can find them in my coursework. Then I shall attempt to help you.

Answer 6

Thanks :)

Answer 7

Okay it wasn't the exact same problem
Here's what I had and how I worked it out

A boat travels 30 mph. A patrol boat starts 4 hours later from the same place and travels at 35 mph in the same direction. How long will the patrol boat require to overtake the first boat?

Step 1: Let t = time to overtake by patrol boat.

t + 4 = time the first boat is traveling.

rate time distance
first boat: 30 t + 4 30(t + 4)
patrol boat: 35 t 35t
At the time of overtake, the distances of the two boats are equal.

Step 2: 30(t + 4) = 35t

Step 3: Solve 30(t + 4) = 35t.


30t + 120 = 35t

120 = 5t

t = 24 hours


lol idk if that will help but it was worth a shot.

Answer 8

Thanks, but I need speed of the current. Man this is hard ! :/

Answer 9

I'll go post your question in chat :D

Answer 10

a. Christian can do a job in 6 hours. Requesting Boyet to work with him, the two can do the jon in 4 1/2 hours. How long would it take Boyet to do the job alone?

Okay, let the Christian's speed by x, and Boyet's speed y.

Christian can do the job in 6 hours, so the whole work can be expressed as \(6x\);
If they do it together, it will take 4 1/2 hours, whole work can be expressed as \(4\frac{1}{2}(x+y)\)

You now a system, solve for x :)

Answer 11

Why is the whole work equal to the speed times the time required to do it? Let's see

\(\large \frac{\text{Whole work}}{\text{Speed}}=\text{Time}\)

Let's play around a little bit with that

\(\large \text{Whole work}=\text{Time} *\text{Speed}\)

Answer 12

So let's solve it;

Since the whole work is equal, then the two equations above are equal

\(\large \begin{align} 6x&=4\frac{1}{2}(x+y) \\
6x\div 4\frac{1}{2}&=(x+y) \\
3x&=x+y \\
3x-x&=y \\
2x&=y



\end{align}\)

Answer 13

Good, \(2x=y\), what does it mean?

Answer 14

I don't know either. :P

Answer 15

Haha, that mean that y, Boyet's speed, is twice x, Christian's speed.

Answer 16

Therefore, Boyet would take half of Christian's time to do the job, 3 hours.

Answer 17

Is that clear enough? We can go to the second question?

Answer 18

Yep loud and clear.

Answer 19

b. A motorcycle can maintain constant speed of 16 kilometers per hour relative to the water. The boat makes a trip upstream to a certain point is 20 minutes; the return trip take 15 minutes, What is the speed of the current?

I don't quite understand this one, a motorcycle goes in the water? o.o