<span>D) 9.0 x 10^10 km
This is more an exercise in handling scientific notation than anything else. Since we have the distance that light travels in 1 second and we want to calculate how far it travels in 5 minutes, we must first calculate how many seconds are in 5 minutes. Simply multiplying 5 by 60 gives us 300 seconds. Now we need to multiply 300 by 3.0x10^8 km. So
300 * 3.0x10^8 = ?
We could first convert 300 into scientific notion, but it's easier to just leave it along and assume that it's 300 x 10^0. So 300 times 3 is 900. And since 0 plus 8 is 8, we have as the answer:
900 x 10^8
But we're not done. The significand has to be greater than or equal to 1 and less than 10. So let's divide 900 by 100 and add 2 to the exponent. So we get
9 x 10^10
Finally, since our data had 2 significant figures, our result should have that as well. So let's add the 2nd digit getting:
9.0 x 10^10
So we know that light travels 9.0x10^10 km in 5 minutes, and that answer matches option "D" from the available choices.</span>
3:1 =300%
2:3:5 =50%
1:4 =25%
1:2:5 =62.5%
Answer:
x+y/4 = 1/2
x-3y/3 = 2
move variables to one side:
multiply the first equation by 4 to get: x+y =2
and the second equation by 3 to get: x-3y =6
then subtract the equations to cancel out x:
x+y = 2
- x-3y = 6
then u get
y--3y = 2-6
4y = -4
y=-1
substitute to solve for x:
x-1 / 4 =1/2
x-1 = 2
x=3
check:
3+-1
2/4= 1/2
correct!!!
The correct answer is B. So for A, 8m is smaller than 12 m. For B, 20 m is Bigger. For C, Find how many meters is 1 centimeter, the answer is 1 cm : 12m, the meter is not bigger than 12, but the same, so C is wrong. For D, divide both sides by 3 to find 1 CM, the answer is 1 cm : 5 m, it is wrong.
Answer:
10.75 would be a 64 ring size in the US
