The question is:

Maudes spends all of her income on delphinium and hollyhocks.

Maude thinks delphiniums and hollyhocks are perfect substitutes, one for one. If delphiniums currently cost $4 per unit and hollyhocks cost $5 per unit and if the price of delphiniums rises to $7 per unit,

We have therefore an utility function of 1=1, that is U(xd,xm) = xd+xm:

I'm confused about the question, as it doesn't give Maude's Income. I'm therefore hesitating between answer 2 and 3, as we don't now here income

- 2/3 of the change in demand will be due to the income effect.

- there will be no change in the demand for hollyhocks.

-the entire change in demand for delphiniums will be due to the substitution effect.

-the income effect of the change in demand for delphiniums will be bigger than the substitution effect.

-1/3 of the change in demand will be due to the income effect.