Which strategy would not correctly solve this story problem?

madison washed dishes twice as long as she vacuumed the floors. she washed her dog for 20 minutes more than she vacuumed. she vacuumed the floors for 40 minutes. how many minutes did madison spend on chores?

a.

work backward. madison worked for 40 min and then worked 40 + 20 min (60). then she worked 2 × 40 min (80). add up 40 + 60 + 80 to get the total time madison worked.

b.
draw a diagram. first draw 4 dots (each dot represents 10) for the time madison vacuumed. draw 2 groups of 4 for the time she washed dishes. draw 4 dots and add 2 more for the time she washed her dog. add up all the dots and multiply by 10 to find the total time spent on chores.

c.

use logical reasoning. madison worked for 1 period of 40 min vacuuming and for 2 periods of 40 min washing dishes. she worked 1 more period of 40 min plus 20 more min. that's 4 × 40 min + 20 min.

d.

translate into an equation. 40 + 40 + 40 + 20 = m