# Word Problems

#### faith14

##### New member
I have these 3 word problems I've been trying to figure out but can't seem to get. I could use some help getting the equation.

1. On a test 20 problems were given. Five points were given for each correct answer and 2 points were deducted for each incorrect answer. How many correct answers are required to score 79 on the test?

If you got 16 problems right on the test that would give you an 80 but I don't understand how you would get a 79. Even if you missed one problem, the grade would still be an even number.

2. Write an eight-digit number using the digits 1, 2, 3, and 4 twice each. The 1's should be separated by one digit, the 2's by two digits, the 3's by three digits, and the 4's by four digits.

I don't even know if there is a formula to figure this out. I have just been trying number combinations but have come up with nothing that works so far.

3. Find the numbers that will replace letters a and b so that the five-digit number will be divisible by 36: 19a9b (Note: There are two possible solutions.)

Is there a formula to figure this out or would this be a problem that you would just plug numbers in until it worked? I can plug in the numbers but if there is a formula I would really like to know what it is in case I get another one of these problems.

Thanks for any help!!

#### Subhotosh Khan

##### Super Moderator
Staff member
faith14 said:
I have these 3 word problems I've been trying to figure out but can't seem to get. I could use some help getting the equation.

1. On a test 20 problems were given. Five points were given for each correct answer and 2 points were deducted for each incorrect answer. How many correct answers are required to score 79 on the test?

If you got 16 problems right on the test that would give you an 80 but I don't understand how you would get a 79. Even if you missed one problem, the grade would still be an even number.

17*5 - 3*2

2. Write an eight-digit number using the digits 1, 2, 3, and 4 twice each. The 1's should be separated by one digit, the 2's by two digits, the 3's by three digits, and the 4's by four digits.

I don't even know if there is a formula to figure this out. I have just been trying number combinations but have come up with nothing that works so far.

As far as I know, just educated trial-and-error is sufficient.

I got it after few tries.

Show us some of your work - and discuss your difficulty - so that we can guide you.

3. Find the numbers that will replace letters a and b so that the five-digit number will be divisible by 36: 19a9b (Note: There are two possible solutions.)

Is there a formula to figure this out or would this be a problem that you would just plug numbers in until it worked? I can plug in the numbers but if there is a formula I would really like to know what it is in case I get another one of these problems.

Thanks for any help!!

#### Denis

##### Senior Member
faith14 said:
2. Write an eight-digit number using the digits 1, 2, 3, and 4 twice each. The 1's should be separated by one digit, the 2's by two digits, the 3's by three digits, and the 4's by four digits.
23421314 and its reverse 41312432

#### fasteddie65

##### Full Member
On a test 20 problems were given. Five points were given for each correct answer and 2 points were deducted for each incorrect answer. How many correct answers are required to score 79 on the test?

Here is one possible answer: 17 correct problems would be worth 85 points. 3 incorrect would deduce 6 points. This would give a score of 79.

#### Subhotosh Khan

##### Super Moderator
Staff member
Fasteddy,

Did you see my response? If you did - do you think you taught Faith anything, beyond what i stated??