<span>10x + 30(2) = 20(x + 2)
10x + 60 = 20x + 40
10x = 20
answer
x = 2 liters
So you would need 2 liters of the 10% solution to make the 30% solution 20%.</span>
Answer:
4 hours
Step-by-step explanation:
For three visits, the electrician earned $40 × 3 = $120 in "per-visit" charges. For working x hours, he earned 20x in "per-hour" charges. The total of these came to 50x:
120 +20x = 50x
120 = 30x . . . . . . . . subtract 20x
4 = x . . . . . . . . . . . . . divide by 30
The electrician worked 4 hours that day.
We have to calculate the height of a cylinder : h2 = ( 45 - 2 · 15 )/ 2 = 15 / 2 = 7.5 mm
Volume of the bottom of the hourglass:V = 1/3 r² π h1 + r² π h2 = = 1/3 · 6² · 3.14 · 15 + 6² · 3.14 · 7.5 = = 1/3 · 36 · 3.14 · 15 + 36 · 3.14 · 7.5 = = 565.2 + 847.8 = 1,413 mm³The rate is 10 π mm³/ sec = 31.4 mm³/secTime = 1,413 : 31.4 = 45 sec.Answer: It will take 45 seconds.
-x^2+2x+3=x^2-2x+3 add x^2 to both sides
2x+3=2x^2-2x+3 subtract 2x from both sides
3=2x^2-4x+3 subtract 3 from both sides
2x^2-4x=0 factor
2x(x-2)=0
So x=0 and 2
<u>Answer</u>
24 square units
<u>Explanation</u>
The formula for getting the area of a trapezium is
Area = 1/2 h(a+b0
where h ⇒ perpendicular height
a and b ⇒ length of the parallel sides.
h = 2 - -2 = 4 units
a = 5 - -3 = 8 units
b = 3 - -1 = 4 units
Area = 1/2 × 4(8+4)
= 2×12
= 24 square units.
