Answer:
x = 13
Step-by-step explanation:
The area (A) of a trapezium is calculated as
A =
h (b₁ + b₂ )
where h is the perpendicular height and b₁, b₂ the parallel bases
Here A = 55, h = 5. b₁ = x, b₂ = 9, then
× 5 × (x + 9) = 55
2.5(x + 9) = 55 ( divide both sides by 2.5 )
x + 9 = 22 ( subtract 9 from both sides )
x = 13
Let us start with assuming the amount of coffee worth $20 a pound to be "x" pounds.
Now she wants to mix "x" pounds of $20 coffee with 70 pounds of $90 coffee.
So the mixture would be (x + 70) pounds.
And the value of mixture would be = 20·x + (90)·(70) = (20x + 6300) dollars.
She want to sell this mixture at rate of $30 a pound. Her earning would be = 30·(x + 70) = (30x + 2100) dollars.
We know that the value of mixture would be equal to her earnings.
30x + 2100 = 20x + 6300
30x - 20x = 6300 - 2100
10x = 4200
x = 420
So, 420 pounds of $20 coffee would be used.
Choice A is the correct answer
Answer:
The simplified form of given expression is 3/5.
Step-by-step explanation:
The given expression is

We need to find the product of two factions using diagram.
For 3/4, draw a box and divide it in 4 equal parts by using vertical lines. The color three parts of it.
For 4/5, draw a box and divide it in 5 equal parts by using horizontal lines. Then color the four parts of it.
Now combined both boxes and shown below.
From the below figure it is clear that
The number of common shaded small boxes = 12
Total number of small boxes = 20
The required fraction is


Cancel out common factor.

Therefore, the simplified form of given expression is 3/5.