75. As she is going up, 15 stairs have been passed by the escalator moving. When she goes down same thing
Answer: n = 75; p = 30
Explanation: (a) 5p + 4n = 450 where p is for pen and n is for notebook.
(b) 10p + 3n = 525
We can use the elimination method to solve these two equations.
1. Multiply the first equation by 2 so that 10p will cancel out:
2(5p + 4n = 450)
- 10p + 3p = 525
10p + 8n = 900
- 10 p + 3n = 525
5n = 375
2. Divide by 5 to get n alone: n = 75
3. Plug 75 into the first equation: 5p + 4(75) = 450
5p + 300 = 450
4. Subtract 300 from 450: 5p = 150
5. Divide by 5 to get p alone: p = 30
We can test if this is correct by plugging our answers into the second equation:
10(30) + 3(75) = 525
300 + 225 = 525
525 = 525
This is a true statement, which means that our answers are correct.
60.
The question gives you the fact that 6 bricks is 2 feet high.
What do you do to get from 2 to 20?
You multiply by 10.
Since you multiplied one thing by 10, you must do it to the other side so it remains balanced.
2 ft x 10ft = 20ft
6 bricks x 10 bricks = 60 bricks
Martha’s new weight is 77.25. 3% of 75 is 2.25 and you can find that by multiplying 75 by .03 and adding that number to 75. hope this helps!
