$40 increased by by 90%

The new price is $76

Step-by-step explanation:

Step 1:  Make an expression

40 * (1 + 0.9) = x

40 * 1.9 = x

Step 2:  Multiply

40 * 1.9 = x

76 = x

 The new price is $76

76

Step-by-step explanation:

To find the new amount, we take the old amount and add the increase

new = 40 + 40*90%

Changing from percent to decimal

        = 40 +40*.90

         =40 +36

         =76

the answer is:

the correct option:

b.

to solve the problem, we need to remember how to operate to simplify exponential expressions using the logarithms.

we are given the equation:

then, using placing logarith with base 7 on both sides of the equation, we have:

so, rounding the obtained result to two decimal places (nearest hundreth), we have:

hence, we have that the correct option:

b.

have a nice day!