Answer: b) 6
Step-by-step explanation:
Given : The illuminance of a surface varies inversely with the square of its distance from the light source.
i.e. for d distance and l luminance , we have
, where k is constant. (1)
If the illuminance of a surface is 120 lumens per square meter when its distance from a certain light source is 6 meters.
From (1), we have
(2)
For the distance (d) corresponds to the illuminance to 30 lumens per square meter , we have
Put value of k , we get
Then , the number of meters should the distance of the surface from the source be increased= 12 meters- 6 meters = 6 meters.
Answer:
it is corect
Step-by-step explanation:
Answer:
A
Step-by-step explanation:
If you multiply the price for each mule x the amount of miles + the daily rental, you get the price. If you do this for each option and each car rental then you can see when the answers add up.
.75x56+20=62
.50x56+34=62
Rate is used to compare values of the same unit. So, it is important to convert rates to the same units so that the units can cancel out.
Answer:
x^3 + 1/x^3 = 488
Step-by-step explanation:
- x^2 + 1/x^2 = 62
- x^2 + 1/x^2 + 2 = 64
- ( adding 2 in both sides )
- (x + 1/x ) ^2 = 64
- x + 1/x = 8
now,
- ( x+ 1/x ) ^ 3 = 512
- x^3 + 1/x^3 + 3 × x × 1/x ( x + 1/x )
- x^3 + 1/x^3 + 3 ( 8 )
- ( since x + 1/x = 8 )
- x^3 + 1/x^3 + 24 = 512
- x^3 + 1/x^3 = 488
hence, we got x^3 + 1/x^3 = 488