The price of a carton of eggs at Supermarket A is $\$2.10$ . The price of a carton of eggs at Supermarket B is $40\%$ less than the price at Supermarket A.
What is the price of a carton of eggs at Supermarket B?
The price of a carton of eggs at Supermarket B is $40\%$ less than the price at Supermarket A, which means it is $100\% - 40\% = 60\%$ of the price at Supermarket A.
So the price of a carton of eggs at Supermarket B is $60\%$ of $\$2.10$, which is
$$0.60 \times \$2.10 = \$1.26$$
Therefore, the price of a carton of eggs at Supermarket B is $\$1.26.