Answer:
The last quiz score must be at least an 80 to get the average to be a 70.
Step-by-step explanation:
In order to find this, you need to take the average of the 4 test scores along with the unknown test score (x). So, to find an average, we add all the numbers together and divide by the amount of tests taken. We can then set this equal to 70 since that is the minimum average.
(60 + 64 + 75 + 71 + x)/5 = 70 ------> Multiply both sides by 5
(60 + 64 + 75 + 71 + x) = 350 -----> Combine like terms
270 + x = 350 -----> Subtract 270 from both sides
x = 80
Answer:
x is mL of 25% acid and y is mL of 50% acid
We set up 2 equations:
A) x + y = 250
B) .25 x + .50y = .35 * 250 which equals
B) .25x + .50y = 87.50 Multiplying A) by -.5
A) -.5x -.5y = -125 adding the equations we get
-.25x = -37.50
x = 150 mL
y = 100 mL
Source: http://www.1728.org/mixture.htm
Step-by-step explanation:
Answer:
b
Step-by-step explanation:
Give me brain list plssssss
Answer:
502 m²
Step-by-step explanation:
We require to find b before calculating the surface area.
The volume (V) of a cuboid is calculated as
V = lbh ( l is length, b is breadth and h is height )
Here V = 510, l = b, b = 10 and h = 3, thus
b × 10 × 3 = 510
30b = 510 ( divide both sides by 30 )
b = 17
--------------------------
The opposite faces of a cuboid are congruent, thus
top/bottom area = 2(17 × 10) = 2 × 170 = 340 m²
front/back area = 2(17 × 3) = 2 × 51 = 102 m²
sides area = 2(10 × 3) = 2 × 30 = 60 m²
Surface area = 340 + 102 + 60 = 502 m²
Answer:
168
Step-by-step explanation:
21 x 8 pints in a gallon is 168
