Question 289523
The assumption is that the pool is rectangular.
The perimeter of a rectangle is 
{{{P=2*(L+W)}}}
In this case,the length is 30 meters longer than 6 times the width,
{{{L=30+6W}}}
Substitute in the perimeter equation,
{{{P=2*((30+6W)+W)=1110}}}
{{{30+7W=555}}}
{{{7W=525}}}
{{{W=75}}}
Then from above,
{{{L=30+6W=30+6(75)=480}}}
The pool dimensions are 480m by 75m.