Answer:
257 is prime.
Step-by-step explanation:
To evaluate if a number is prime, we just need to evaluate it for the prime numbers that are equal or lesser than the said number's square root.
In this case, √257 = 16.03 so we just need to see if 257 is divisible by <u>2, 3, 5, 7, 11 and 13</u> (the prime numbers that come before 16)
- 257 is odd, so it is not divisible by 2.
- The sum of its digits is 14, therefore, it is not divisible by 3.
- 257 ends in 7, therefore it's not divisible by 5.
- 257/ 7 = 36.71 so it's not divisible by 7.
- 257/ 11 = 23.36 so it's not divisible by 11
- Finally 257 / 13= 19.76 so it's not divisible by 13.
Therefore, 257 is prime.
Answer:
Step-by-step explanation:
1/4 + 5/8
= (2+5)/8
= 7/8
Answer:
z =23
Step-by-step explanation:
The three angles in a triangle add to 180 degrees.
62+95+z = 180
Combine like terms
157 +z = 180
Subtract 157 from each side
157-157 +z = 180-157
z =23
Dat be called common difference represented by d in the equation
Answer:
7.5
Step-by-step explanation:
The relation between time, speed, and distance is ...
time = distance/speed
If distance is "1 round trip", then the time going is ...
going = 0.5/(10 mi/h) . . . . for 1/2 round trip
and the time coming is ...
coming = 0.5/(6 mi/h)
Then the average speed for the full round trip is ...
speed = distance/time
average speed = 1/(going + coming) = 1/(0.5/10 +0.5/6) mi/h
= 1/((3+5)/60) mi/h
= 60/8 mi/h = 7.5 mi/h
Jack's average speed for the round trip was 7.5 mph.
