Question

Using a venn diagram,a school sports teams contain 68 student,33 do field event,40 did track event, 23 did swimming,14 do both field and track event,8do both swimming and field event.lf15 student do both field event,and 10 do both swimming and track event, how many students did swimming only, track event only,all Three event

Answer 1

You appear to have a typo.
"lf15 student do both field event, " makes no sense
You already stated the 3 possible pair of events.
14 F & T
8 F & S
10 S & T

anyway, hint:
let the number in the intersection of all 3 be x
then fill in 14-x in the F&T only
etc