2 is not a composite number as it can't be divided rather than 1 or other number.
hope it helps!
186cm
You add all the sides up, so 42+42+51+51 which equals 186cm
20 = 2 x 2 x 5
15 = 3 x 5
common divisor (CD) of 20 and 15 is 5 so n should be 5 and each group has 4 boys and 3 girls.
If there are more than one CD, then there are more than one answer.
If they ask for the largest number of groups, greatest common divisor (GCD) will be the answer.
Answer:
x + y = 5
<u>3x - 4y = 8</u><u> </u><u> </u><u> </u>
3x + 3y = 15
<u>3x - 4y = 8 </u>-
7y = 7
y = 1
x + y = 5
x + 1 = 5
x = 4
x = 4
y = 1
Hope it helps!