Answer:

except 2 all are in proportion

Step-by-step explanation:

we know that product of means =product if extreme

1. since product of means =product of extreme

so,

12×8=16 ×6

96= 96

so 12,16,6,8 are in proportion. .

2. . since product of means =product of extreme

so,

2×5=4×3

10=12

which is not possible

so 2,3,4,5 are not in proportion.

3. since product of means =product of extreme

so,

18×5=9×10

90=90

so 18,9,10,5are in proportion.

4. ques 3 and 4 are same.