Work back method

if each modem costs 1$, then total cost is 4000$. If the cost increases by 25%, then the cost will be 5$

d=4000
Then substitute the value in given options to get an answer of 5$

1. d/800=4000/800=5$
2. 5d/1000= 20,000/1000= 20
3. 125d= NS
4. d/1000+25= 29
5. 125/1000d= NS

Finally answer A

hi
i think the answer is A
and for this type of question the simple approach is
1000 modems total cost is d
per modem cost = d/1000
now the price is increased by 25% (which is 1.25 as multiplier)
price of each modem is = d*1.25/1000
= d*5/4*1000
= d/800

thanks and regards

My answer is A.
Bcz
Per modem cost = d/1000
SP = d/1000 * (1.25)
= d/800

A indeed

d/1000 *1.25 = d/800

nikhilgmat31 wrote:A indeed

d/1000 *1.25 = d/800

No need to revive this thread, though!