This is a question where the difference remains unchanged.

Number of stalks of roses
= 84 x 4
= 336

Difference between stalks of roses and orchids
= 336 - 84
= 252

Since the same number of orchids and roses were bought, the difference remains the same at 252.

Now, since the ratio is now 5:9,
Difference = 9 units - 5 units
= 4 units

252 = 4 units
1 unit = ?

From here you should be able to solve it on your own.

Question seems undoable. J's method may be correct but you'll end up with 315 orchids and 567 roses remaining. Which is more than the initial.


Using algebra to solve this, i.e. x is the number of roses/orchids bought, to solve this will result in a negative x value.

The question is doable. It is not asking for how many stalks of each that are remaining.

It is asking how many stalks of roses and orchids the florist bought altogether. So it is just the difference between the total number of stalks of flowers at first and at the end. Note that the florist already had 84 stalks of orchids and 4 times that of roses at the start. She just bought more, and an equal number of each.

Oh chey, I thought a customer bought

Thank you so much Abel :)
I understand much better now

Np, J did most of the work