I am not good at drawing. Tell me about it. There are two ways to do this. One is to do it at equal distances. The second is to do it according to the equality of time.

The first method: 40t 1+4t2=7.

4t 1+4t3+40(t3+t2)=7

40t 1-50t3=4t 1+4t3

The second method: (7-s 1-s2)/50=s3/4.

(S2-S3)/4+S3/4+(7-S2)/40 =(7-s 1)/40+s 1/4

(s2-s3)/4=(7-s 1)/40