the complete question in the attached figure
step 1
find the area of the wall
[area of the wall]=[area of rectangle]+[area of triangle]
[area of the wall]=[3*2]+[3*1/2]----> 7.5 m²
1 m²-------> 10.7639 ft²
area of the wall------> 7.5*10.7639------> 80.73 ft²
we know that
1 can of paint covers an area of --------> 24 ft²
x---------------------------------------------> 80.73 ft²
x=80.73/24---------> x=3.36 can of paints
the answer is
The fewest number of cans is 4