It is 639.5. this is how you round numbers to the nearest tenth:
if the digit in the hundredths place is 5 or more you round up one, if it is lower than 5 it stays the same, pay no attention to the thousandths place....ex--> 0.497
the 4 is the tenths place
th 9 is the hundredths place
the 7 is the thousandths place......since 9 is 5 or more you round the 4 up one number, so the 4 would be a 5. pay no attention to the 7. lets do another
0.426
the 4 stays as a 4 because 2 is a lower number than 5.
Answer:
After 15 minutes, the temperature of both the furnaces will be same.
Step-by-step explanation:
Let
be the minutes when the temperature of both becomes same.
Now, as per question:
Temperature of the furnace after
minutes that is cooling at the rate of 15 degree per minute is given as:

Temperature of the furnace after
minutes that is heating at the rate of 5 degree per minute is given as:

Now, equating both the temperatures, we get

Therefore, after 15 minutes, the temperature of both the furnaces will be same.
Option B:
Both n and m must be rational.
Solution:
Given information:
Sum of two numbers, n and m are rational.
<u>To find which statements are true:</u>
Option A: Both n and m may be rational but do not have to be.
It is not true because n and m given is rational.
It have to be rational.
Option B: Both n and m must be rational.
Yes, n and m must be rational then only the sum of numbers are rational.
It is true.
Option C: Both n and m must be irrational.
Sum of irrationals will be sometimes irrational and sometimes can't add.
So it is not true.
Option D: One number is rational and the other is irrational.
Rational and irrational cannot be add.
So it is not true.
Option B is true.
Both n and m must be rational.
Answer:
It would be like counting up fives
Step-by-step explanation:
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