Question

what number must be added to 480 and 400 to each 9:16 to get2:3​

Answer 1

9:16 of 480

480/(9+16) = 480/25 = 19.2

19.2 x 9 = 172.8

19.2 x 16 = 307.2

Hence 172.8 & 307.2

2:3 of 400

400/(2+3) = 400/5 = 80

80 x 2 = 160

80 x 3 = 240

Hence 160 & 240

Sorry if your question was something else because it's not clear.

:-)