The sum of all positive integers less than 400 which are divisible by 5.

sum = 15800

Step-by-step explanation:

The sum of all positive integers less than 400 which are divisible by 5. The last number divisible by 5 that is less than 400 is 395.

Arithmetic progression can be used to solve this. We will first find the number of term that can give us 395 since that is the last term that is less than 400 and can divide 5.

first term = 5

difference = 5

n = number of terms

nth term = a + (n - 1)d

395 =  5 + (n - 1)5

395 = 5 + 5n - 5

395 = 5n

n = 395/5

n = 79

The sum of this term can be computed as

sum = n/2(a + l)

a = first term

l = last term

sum = 79/2 (5 + 395)

sum = 79/2 × 400

sum = 31600/2

sum = 15800

unless you made a typo, the answers are both a and c.

step-by-step explanation:

1.5/3 is .5 whereas 3/9 is .3333333 not proportional

22/33 is .66666 and 4/6 is also .66666 proportional

2/4 is .5 whereas 142/213 is .66666 not proportional

14/7 is 2 and 7/3.5 is also 2 proportional

you could've also checked it by doing this simple division:

if the larger fraction divides with the smaller fraction to equal 1, it is proportional. so let me show you what i mean:

when i divide 22/33 by 4/6 i get 1, so we know it is proportional, and it is the same with 14/7 and 7/3.5. now if i divide 3/9 by 1.5/3 i get .66666 so therefore we know it is not proportional.

there are many ways to do this so i wanted to show you some possible ways.

the best estimate is 3 because   8 can only go into 24 3 times