If ruling gradient is I in 20 and there is also a horizontal curve of radius 76 m, then the compensated grade should be

Sol
Here,
Ruling gradient= 1 in 20, 1/20=0.05, 0.05×100%=5%
Radius of curve(R)=76m
Then,
Grade compensation=30+R/R %
=30+76/76
=1.39%
Max. amount of grade compensation=75/R %
=75/76
=0.98%
Take min. Value,
Grade compensation=0.98%
Compensated grade=Ruling gradient -Grade compensation
=5%-0.98%
=4.02% it's near to 4%
The answer is Option B

Maximum value of { 30 +R /R , or 75/R
= (30+76) /76 , or 75/76
= 1.39, or .98
Maximum value = 1.39
Here, rolling gradient= 1÷20 = 0.05 × 100% = 5%
So, 5% - 1.39% = 3.61%
Since, minimum grade compensation= 4% , maximum= 6.7%
So, here results came as 3.61% (should consider minimum grade compensation of 4%)
So, answer is = 4%

Rulling gradient=1:20=5 %
Grade Compensation(%)=(30+76)/76=1.39
Maximum limit of grade compensation=75/76
=0.986
Compensated Grade=5-(.986)=4.014>4
Therefore compensatwd grade will be 4 %