$15 if worn, $30 in better shape.
In worn condition, about $5. In better shape, around $10.
Even though your bills have the phrase "redeemable in gold" on them they're Federal Reserve Notes rather than gold notes. $10 gold certificates were also printed in the 1928 series but they don't have any series letters. 1928 A $10 FRNs are definitely worth more than 1928 B bills, but the difference depends on the issuing Federal Reserve Bank letter. Please see the questions "What is the value of a 1928 A US 10 dollar bill?" and " ... 1928 B ... " for more information.
The value of a 1928 or 1934 $10 bill in circulated condition typically ranges from $20 to $50, depending on its condition and rarity. Uncirculated bills can have a higher value, sometimes reaching over $100. It's recommended to have a currency expert evaluate the specific bill for a more accurate appraisal.
Yes. The 1928 series was the last for circulating gold certificates, and $10 was the lowest denomination. There's more information at the question "What is the value of a 1928 US 10 dollar gold certificate?"
Not every old bill is automatically a certificate so it's important to check carefully. If it has a gold seal and says "Gold Certificate", see the question "What is the value of a 1928 US 10 dollar gold certificate?" for values. If it has a green seal and says "Federal Reserve Note", it's not a certificate, it's a Federal Reserve Note. See the question "What is the value of a 1928 US 10 dollar Federal Reserve Note?" for values.
If circulated, retail prices range from $10 to $20 depending on condition.
The Central bank of China issued notes denominated in Dollars, not Yuan during 1928. It is possible that your note is a regional or industry produced note. An estimated value could only be possible with more detail. The 1928 issue $10 note is mostly worth $3-$7, except a few variations (based on signatures) which are worth as much as $25. In used condition they are mostly worth around $1.
Please don't assume that every old bill has to be a silver certificate. 1928 $10 bills were issued as gold certificates with gold seals and as Federal Reserve Notes, with the familiar green seal and the words "Federal Reserve Note" across the top.Please check the bill's seal color and wording across your bill's top front; then see one of the following questions:"What is the value of a 1928 US 10 dollar Federal Reserve Note?""What is the value of a 1928 US 10 dollar gold certificate?"
depending on the condition, ≈$5~10
Retail is 5 to 10 dollars depending on how worn it is
The value of a 1928 green-seal $5 note depends a lot on what letter, if any, is next to the date. As of 10/2011 approximate retail prices are:1928, 1928ACirculated: $8-$35Uncirculated: $80-$1001928B$8-$20$50-$701928C$200-$650$19001928D$400-$1000$2500
Please check your bill again and post a new, separate question. The US didn't print any 1926-dated bills. The closest date would be 1928, but all 1928 FRNs had green seals. The only red-seal $10 FRNs were in the 1914 series.