Final answer:
The new price of an item after a 40% increase from the original price d can be represented by the expression 1.4d, which reflects the original plus the increased amount.
Step-by-step explanation:
If an item costs d dollars and its price increases by 40%, the new price is often expressed as d + 0.4d. This equation translates to 1d + 0.4d, which simplifies to 1.4d. Therefore, the expression 1.4d also correctly represents the new price of the item after the 40% price increase.