You borrow money for 4 years. the total amount that you repay is $7,840, which includes $840 in simple interest. how much was the principal? what was the annual interest rate?

Step-by-step explanation:

amount repaid = principal + interest

$7840 = principal + $840

$7000 = principal . . . . . . . . subtract $840 from both sides of the equation

___

I = Prt

840 = 7000·r·4

840/(4·7000) = r = 0.03 = 3%

The principal was $7000; the interest rate was 3%.

answer: the answer is (b) amie should have multiplied

step-by-step explanation: given a sphere and a cylinder with same radius and height.

let, 'r' be the radius of the cylinder and sphere and 'h' be the height of the cylinder. according to the question,

r = h.

now, the volume of the sphere will be

and the volume of the cylinder will be

therefore, we have

thus, ammie should have multiplied the volume of the sphere

explanation:

infrared radiation has wavelength in the range between 700 nm and 1 mm. lets' convert these values into scientific notation, keeping in mind that:

let's start from the lower value, we have:

(we moved the dot two places to the left, so we increased the exponent by 2 units, from -9 to -7)

the higher value is:

so, the range of wavelength of infrared radiation is: