Distance - Miles

[Guest]

Railroad ties are placed 18 inches apart from center to center. A total of 54,320 ties are used. Determine distance in miles the ties will cover.

Check my solution:

18 inches = 1.5 feet

1 mile = 5280 feet

54320 / 1.5 = 36213.333 feet = 6.858522 = 7 miles

54320 / .75 (center of tie) = 75426.66 feet = 13.717 = 14 miles

Where did I miscalculate ?

[Guest]

If 10 ties had been used each 1. 5 feet apart the distance covered would be 10 x 1.5 = 15 feet
If 100 ties had been used each 1. 5 feet apart the distance covered would be 100 x 1.5 = 150 feet
Can you not see you would multiply the distance between each ny the number of ties used.

Note also.....If you want to start with a tie at each end....then for 10 ties used there are only 9 spaces of 1.5 feet
So distance covered would be 9 x 1.5 = 13.5 feet.

and Note also.....If you want to start with a tie at each end....then for 100 ties used there are only 99 spaces of 1.5 feet
So distance covered would be 99 x 1.5 = 148.5 feet.

So 1000 = 999 x 1.5 = 1498.5

So 54320 used would be......................

..............................Simple...............................

[Guest]

54319 x 1.5 = 81478.5 / 5280 = 15.4315 miles.

"Can you not see you would multiply the distance between each ny the number of ties used."

I was thinking I needed to divide instead of multiply.

[Guest]

Yes, that is it now..............
You divide to split or divide things into individual parts

The question gave you the number of parts.....so multiply to group them together and get the total

[Guest]

Thanks.