Alright, lets get started.
Suppose the original deck size: width = x feet
the width is one-fourth the length given in question means length = 4 x feet
Means the originally area =
Now the dimensions are changed.
New dimensions, width = (x + 6)
new length = (4x+10)
So, new area will be =
the area of the new rectangular deck is 128 ft2 larger than the area of the original deck, means
Subtracting from both sides
Subtracting 60 from both sides
Dividing 34 in both sides
Means width = 2 feet
Length would be = 4 time width = 4 * 2 = 8 feet
Means dimension of original deck would be = 2 feet and 8 feet :Answer
Hope it will help :)