Answer:
Step-by-step explanation:
hello :
r+b=7... (*)
3.75r+2.75b=22.25.... (**)
use (*) : r = 7 - b
put this value in (**) :
3.75(7 - b)+2.75b = 22.25
26.25 -375b +2.75b = 22.5
-375b +2.75b = 22.5 - 26.25
- b = -3.75
so : b = 3.75
but : r = 7 - b
r = 7 - 3.75
r = 3.25
Answer:
If every sixth student received a pencil and every ninth student received a notebook, 5 participants received both a pencil and a notebook.
Hope this helps!!
Using mixture formula:
Let volume be v, % be p
1 should be the first mixture, 2 should be the second mixture, 3 should be the final mixture.
p₁v₁ + p₂v₂ = p₃v₃
p₁ = 25%, v₁ = 40 p₂ = 60%, v₂ = ? p₃ = 30%, v₃ =?
Let v₂ = x, v₃ = total volumes = v₁ + v₂ = (40 + x)
Using:
p₁v₁ + p₂v₂ = p₃v₃
25*40 + 60*x = 30*(40 + x)
1000 + 60x = 1200 + 30x
60x - 30x = 1200 - 1000
30x = 200
x = 200/30
x = 20/3
Recall x = v₂, so she has to add 20/3 milliters of the 60% solution in order to obtain 30% solution.
I hope this explains it.
Answer:
5(c)
Step-by-step explanation:
The number of chairs are being multiplying by each row.
If you need more help here's info.
Long multiplication is a method of multiplying two numbers which are difficult to multiply easily.
For example, we can easily find the product of 55 × 20 by multiplying 55 by 2 and then adding a 0 at the rightmost place of the answer.
55 × 2 = 110 and 55 × 20 = 1100.
But, many a time finding the product is not this easy. At such times we use the long method of multiplication.
Steps to multiply using Long Multiplication
Multiplying 2-Digit by 2-Digit Numbers
Let us multiply 47 by 63 using the long multiplication method.
1. Write the two numbers one below the other as per the places of their digits. Write the bigger number on top and a multiplication sign on the left. Draw a line below the numbers.