Tamara borrowed $6,000 at 6% and ended up paying $900 in simple interest. For how long was the loan?

I = prt

900 = 6,000 * 0.06t
900 = 360t
900/360 = t
2.5 = t

If 45% students of a class has taken mathematic and 85% students has taken biology find the percentage of such students of a class who have taken biology.

2.5 years

To find out how long Tamara had the loan, we can use the formula for simple interest:

Interest = Principal x Rate x Time

We are given that Tamara borrowed $6,000 at a rate of 6% (0.06 in decimal form) and paid $900 in interest. We can substitute these values into the formula and solve for Time:

$900 = $6,000 x 0.06 x Time

Now we need to isolate the variable Time. Let's divide both sides of the equation by ($6,000 x 0.06) to get:

Time = $900 / ($6,000 x 0.06)

Now we can calculate the answer using a calculator:

Time ≈ $900 / ($6,000 x 0.06) ≈ $900 / $360 ≈ 2.5 years

Therefore, Tamara had the loan for approximately 2.5 years.