There is a total of 270 men women and children on a train the ratio of men to women is 4: 5 the ratio of women to children is 10: 9 how many men are on the train

80

Step-by-step explanation:

Let's say M is the number of men, W is the number of women, and C is the number of children.

M + W + C = 270

M/W = 4/5

W/C = 10/9

We have three equations and three variables, so we can solve this.  Let's use substitution.

W = 5/4 M

C = 9/10 W

Substitute into the first equation:

M + 5/4 M + 9/10 W = 270

Substitute again:

M + 5/4 M + 9/10 (5/4 M) = 270

Solve:

M + 5/4 M + 9/8 M = 270

8/8 M + 10/8 M + 9/8 M = 270

27/8 M = 270

M = 80

There are 80 men on the train.

the first one, all those points on the line just make a strait line.