Posted by **Reiny** on Wednesday, May 9, 2007 at 5:09pm.

You did not watch your units, you are mixing inches and feet

Your equation should have been

1/2 = 1/di + 1/120 (I changed 10 feet to 120 in)

solve this for di and you get 2.03 inches.

Please help me I am so confused I think I am losing my mind.

The focal length f of a camera lens is 2 inches. The lens equation is 1/f=(1/di)+(l/do), where di is the distance between the lens and the film and do is the distance between the lens and the object.

The object to be photographed is 10 ft away. How far should the lens be from the film?

my work:

1 1 1

- = - + -

f di do

1 1 1

- = - + -

2 di 10

You subtract 1/10 and get 4/10=1/di. di=2.5

but supposedly the answer is 2.03. How?

1 1 1

- = - + -

f di do

if you can't tell what i mean, this is it: 1/f=(1/di)+(1/do)

Lol, trick question! Thank you!

## Answer This Question

## Related Questions

- Math last two questions - Leslie needs 324 inches of fringe to put around the ...
- math - solve and writein simplest terms: 3 yards 1 foot 10 inches+ 5 yards 2 ...
- Math - If Sally places a rocket that is 3 feet 6 inches tall atop a launch pad ...
- math - Using this formula: V=LWH Find the volume(v)of a toy box with length (L) ...
- Math - Calculate the Volume in Cubic Feet of a section of drainage pipe that ...
- Math - PLEASE HELP ASAP!!! 1 rectangular prism has a base area of 120 square ...
- math - Robert planted pumpkins to sell. Their garden has 5 sides. 5 feet 8 ...
- math - DAN WAS WALKING FROM ONE END OF THE MALL TO THE OTHER END. HE TOOK THE ...
- 5th grade - Can you please help with the following questons: 1. Duran was ...
- Math - The separation between goalpost uprights in college football changed from...

More Related Questions