Answer:
Mr. Johnson can arrange 18 students in each row, that is 4 rows of boys and 5 rows of girls.
Explanation:
Given:
Number of boys = 72
number of girls = 90
We need to arrange students in rows with equal number of only boys and only girls.
To find the maximum number (x) of boys or girls in each row, we will find the GCF (Greatest Common Factor) of the numbers 72 and 90, such that 'x' divides both numbers evenly without a remainder.
Now to find GCF we will factorize both numbers.
![72 = 2*2*2*3*3](https://img.qammunity.org/2021/formulas/mathematics/high-school/iibmvhdrdzd1ila6gsw9fu6au7bs8b0psv.png)
![90= 2* 3* 3* 5](https://img.qammunity.org/2021/formulas/mathematics/high-school/2d9z8jdpv7y9rf29xv9le771ciqnghvxdc.png)
from above we can say that;
GCF =
![2* 3* 3 = 18](https://img.qammunity.org/2021/formulas/mathematics/high-school/ddq2lx13xxvx27eeigyeycj3bf2s79qta9.png)
Hence Mr. Johnson can arrange 18 students in each row, that is 4 rows of boys and 5 rows of girls.