Answer:
Tahiya attempted 3 incorrect answers.
Helmin attempted 11 incorrect answers.
Step-by-step explanation:
Correct = +4
Incorrect = -3
1) Tahiya got 12 correct answers and scored a 40, the number of incorrect answers was:

2) Helmin got 5 correct answers and scored a -14, the number of incorrect answers was:

In both cases the number of incorrect answers obtained is a fraction, which means that either the data provided is inaccurate, or that the scores obtained by the students are approximate. Let's round the number of incorrect answers to the nearest whole answer.
Tahiya attempted 3 incorrect answers.
Helmin attempted 11 incorrect answers.
Number of cars washed by the eight teams per hour = 2 * 8 = 16 cars.
Number of cars washed by the eight teams in 5 = 16 * 5 = 80 cars.
The teams should charge $600/80 = $7.50
When dividing with negative and positive, the quotient is negative. 70 / -3.5 would be -2. Here is what the long division looks like:
You could set up a proportion to figure out the anwer. 15 hurdles/60%=X hurdles/100%. Cross multiply, 1500=60x. Divide by 60, 25=X=total amount of hurdles. Hope this helps!