10 because there is 4 zero's behind the one. Hopes this helps!! :)
Sadie finished her walk at 3:45 pm
Answer:
270 seconds
Step-by-step explanation:
Melissa's time = x seconds
Abby's time = (x + 30) seconds
Abby walks at a speed of 8 feet per second, and Melissa walks at a speed of 9 feet per seconds.
But, speed =
For Abby,
8 =
distance = 8(x + 30) ................. 1
for Melissa,
9 =
distance = 9x ............. 2
From equations 1 and 2, for the same distance;
8(x + 30) = 9x
8x + 240 = 9x
x = 240 seconds
Abby's time = (x + 30)
= (240 + 30)
= 270 seconds
So that Abby has been walking for 270 seconds when both students had walked exactly the same distance.
i can not give the answer unless you still cannot find it after these steps but I have steps that might help
1. Set the matrix (must be square).
2. Reduce this matrix to row echelon form using elementary row operations so that all the elements below diagonal are zero.
3. Multiply the main diagonal elements of the matrix - determinant is calculated.