At the beginning of 1990, Jon and Krista each purchased a certificate of deposit that paid the same rate of interest, and each held the certificate of deposit through the end of 1990. If Jon invested x dollars and Krista invested $10,000, and if Jon earned interest in 1990 totaling $1200, what was the amount of interest that Krista earned on her $10,000 investment?
Jon: x dollars --> $1200;
Krista: $10,000 --> ?
(1) The rate of interest on the certificate of deposit that Jon and Krista each purchased was 6 percent. We can calculate the amount of interest on Krista's $10,000. Sufficient.
(2) In 1990, Jon invested $20,000 in the certificate of deposit. Thus Jon earned $1200 on his $20,000, which is 6%. Since we are told that their investments paid the same rate of interest, then we can calculate the amount of interest on Krista's $10,000. Sufficient.
Answer: D.