Question

What is happening here [ http://prntscr.com/8jajiq ]

Answer 1

Maths happening yo

Answer 2

Wouldn't it be \[120x - 3600 \space \space NOT \space \space 120x - 120 \times 30\]

Answer 3

Logic being: -120 * 30 - 3,600

Answer 4

@Compassionate If you calculate the value of -120 * 30 when it arises, the final result of the calculation of the value of x does not change.

Answer 5

Come again? Put that in idiot terms for me.

Answer 6

120x - 3600 = 80x
40x = 3600
x = 90

Answer 7

@Compassionate Are you there?

Answer 8

\[120x - 3,600 = 80x \space \space \space, \space \space \space 40x = 3,600 \space \space \space , \space \space \space x = 90\]

Answer 9

Oh, I get it. So, we can solve it by multiplying out regularly, just the tutorial I am doing does it weird and shows the processes. That's what confused me. And since we know x - 30, we just say 90 - 30.

Answer 10

Can we do one more?

Answer 11

Sure. Go ahead.

Answer 12

Train A has a speed 15 mi/hr greater than train B. If train A travels 150 miles in the same time train B travels 120 miles, what are the speeds of the two trains?

Here is my logic.

Train A = x + 15.

\[\frac{ 150 }{ x +15} = \frac{120}{x}\]

Answer 13

150x = 120x + 1,800
30x = 1,800
x = 60
Recalling x + 15 for A's speed, 60 + 15 = 75

Answer 14

All good.

Answer 15

Thanks a lot, man. I don't usually fan people, I only have a handful, maybe 9 -10, but I'll shoot you a fan because you're quite helpful.

Answer 16

Thank you and you're welcome :)