Question 515176
"Kathy bicycles 4/km/h faster than Robert" ___ K = R + 4


"In the same time it takes Robert to bicycle 57 km, Kathy can bicycle 69km" ___ t = d / r
___ the times are the same (equal) ___ (57 / R) = (69 / K)


"cross" multiplying ___ 57K = 69R


substituting ___ 57R + 228 = 69R


solve for R and substitute back to find K