Well, the last digit in the product will only come from the last digits of the numbers that you're multiplying together. So for 0.303 & 4.48, that last digits are 3 & 8 so that last digit in the product would come from

So 4. There are only two options that end in 4, 1.35744 & 0.13574. You can by the magnitude of the numbers that it isn't as small as 0.13574 so the answer must be 1.35744.
I think the answer is probably b or c
Quadratic formula is x = -b+ or- sq rt b^2-4ac / 2a
a=2 b=5 c=-3
-5 +or- sqrt 5^2-4(2)(-3) / 2(2)
-5 +or- sqrt 49/ 4
-5 + 7 /4 = 2/4 = 1/2
-5 - 7 /4 = -12/4 = -3
Factoring a*c is 2*-3 =-6
Factors of -6 that add to 5 are 6 and -1
Split 5x into +6x-1x
2x^2+6x-1x-3 and group
2x(x+3)-1(x+3)
(x+3)(2x-1)=0
x+3=0 gives x=-3
2x-1=0 gives x=1/2
It took them 4 days to install 480 chairs which means if they were working at a constant rate they got 120 chairs installed daily. with 360 chairs left that means in 3 days they will finish. so overall, it took the workers 7 days to finish, or a week.
Multiply 9800 by . 2. Then multiply that answer by 15 to get the answer. hope that helps!