Problema Solution
Loyola Heights has 3000 phones of which 3/5 are dial phones. If 2/3 of these dial phones are replaced by digital phones and 400 additional digital phones are installed, what fraction of the phones are digital now?
Answer provided by our tutors
dial phones: (3/5)*3000 = 1800
digital phones: 3000 - 1800 = 1200
(2/3)1800 = 1200 dial phones are replaced by digital
after the replacement:
1800 - 1200 = 600 dial phones
1200 + 1200 = 2400 digital phones
400 additional digital phones are installed
after the additional digital phones installed:
600 dial phones
2400 + 400 = 2800 digital phones
the fraction of digital phones from the total number of phones is:
2800/(2800 + 600) = 2800/3400 = 14/17