Question 1199093

To get from point {{{M}}} (on the outside of cylinder) to point {{{N }}}(on the inside of cylinder), ant must go up {{{12-4 = 8cm}}}, then it must go down{{{ 12-10 = 2cm}}}. 

So the ant must move vertically {{{8+2 = 10cm }}}and horizontally {{{15/2 = 7.5cm}}}

{{{x}}} = length of shortest path from point {{{M }}}to point {{{N}}}

{{{x^2 = (10cm)^2 + (7.5cm)^2 = 156.25cm^2}}}

{{{x = 12.5cm}}}

Once it reaches top, it has already travelled {{{8/(8+2) = 4/5}}} of total distance.

So it has just {{{1/5}}} of distance left to get to {{{N}}}

= {{{12.5cm/5}}}

= {{{2.5cm}}}



answer: D) {{{2.5}}}