Respuesta :
Multiply 30 by 80% - or 0.8.
The resulting number is how many questions he got right.
Subtract that number from the total of 30, and you'll know how many he got wrong.
You can also do it as a fraction - 80% out of 100% is 80/100, or 4/5. So he got 4/5 right and 1/5 wrong.
30 multiplied by 1/5 is the same as 30 divided by 5. So 30 divided by 5 will be how many questions he got wrong.
The resulting number is how many questions he got right.
Subtract that number from the total of 30, and you'll know how many he got wrong.
You can also do it as a fraction - 80% out of 100% is 80/100, or 4/5. So he got 4/5 right and 1/5 wrong.
30 multiplied by 1/5 is the same as 30 divided by 5. So 30 divided by 5 will be how many questions he got wrong.