If T and R are tread and rise respectively of a stair, then

ANS:A - 2R + T = 60

1. 2R+T=60: This equation suggests that twice the rise plus the tread equals 60. This equation implies that the sum of twice the rise and the tread should be 60 units, which is a reasonable assumption for stair dimensions.
2. R+2T=60: This equation suggests that the rise plus twice the tread equals 60. This equation implies that the sum of the rise and twice the tread should be 60 units, which is not a typical scenario for stair dimensions.
3. 2R+T=30: This equation suggests that twice the rise plus the tread equals 30. This equation implies that the sum of twice the rise and the tread should be 30 units, which is less than a typical stair dimension.
4. R+2T=30: This equation suggests that the rise plus twice the tread equals 30. This equation implies that the sum of the rise and twice the tread should be 30 units, which is less than a typical stair dimension.
5. R+27=30: This equation seems to be unrelated to the relationship between the tread and the rise of a stair. It suggests that three times the rise plus 27 equals 30, which doesn't correspond to the standard formulation for stair dimensions.