Answer:
2.4 hours
Step-by-step explanation:
Let total work = X
Rate of work done = X ÷ time
Rate of A = X/4
Rate of B = X/6
If they work together, rate is the sum of their individual rates, i.e.
X/4 + X/6
= (3X + 2X)/12 (taking LCM)
=5X/12
Rate = X/time
5X/12 = X/time
time = X÷(5X/12)
time = X × 12/(5X)
time = 2.4 hours
Shortcut:
Product of individual times/sum of individual times
= (4×6)/(4+6)
=24/10
=2.4 hours
Answer:
B. 12.5
Step-by-step explanation:
We have the lowe confidence interval = 185
The upper confidence interval = 210
Mean of X = (lower confidence + upper confidence interval)/2
Mean of X = 185 + 210/2
= 197.5
The margin of error = the upper confidence interval - mean of X
= 210-197.5
= 12.5
First one is 9/10 second is 1 2/5
<span>Let the extension of the length and width be x.
The new dimensions are: Length = 8+x
Width =3+x
Area = 104 ft squared
Area of a rectangle = Length x Width
Therefore,
(8+x)(3+x) = 104
x^2 +11x +24=104
x^2 +11x +24-104=0
x^2 +11x-80=0
Factorize using splitting the middle term method.
X^2 +16x-5x-80=0
x(x+16)-5(x+16)=0
(x-5)(x+16)=0
either x-5 = 0 or x+16=0
x=5 or x=-16
length and width measure cannot be negative.
Therefore, the extension of the length and width is 5 feet each.</span>
