A split-total percent-change question calls for a share ledger: write each category as a share of the original total, then apply its own change. If the starting shares are unknown, set the changed pieces equal to the given new total and use a Desmos regression to solve. To find a final share, divide by the new total, not the original one.
Hints
- Hint 1
The two sources make up the entire 2025 total, so their starting shares add to . If online sales have a share of , what is the in-store share?
- Hint 2
A percent-change factor tells you how much of an amount remains: a increase gives , while a decrease leaves . Multiply each 2025 share by its own factor.
- Hint 3
A total decrease leaves per of 2025 revenue. After finding the starting split, compare online's 2026 amount with the 2026 total.
Step-by-step
Build a share ledger and solve in Desmos
Step 1Write the 2025 shares
Count the 2025 total as . Let be online sales' share, or portion, of that total. Revenue came from only two sources, so the in-store share is .
- Step 2
Turn the changes into a total-revenue equation
Online sales rise to per of 2025 revenue. In-store sales fall to . The total falls by , leaving per of 2025 revenue. Add the separately changed pieces to match that total:
- Step 3
Find the starting online share
In Desmos, type . Use for and for : a regression finds the value of that fits the equation. Under PARAMETERS, Desmos shows . That's the 2025 online share, not the share the question asks for.
- Step 4
Find online revenue after its increase
Add on the next Desmos line. It prints . This contribution is 2026 online revenue measured against the 2025 total. Stopping here would use the wrong year's total for the requested share.
- Step 5
Compare online revenue with the 2026 total
Add in Desmos. It prints . For a 2026 share, divide the 2026 online amount by the 2026 total. So approximately of the company's 2026 revenue came from online sales. Choice B.