if the following was taken during your sounding process Dept 1m value 1000litres,

dept 2m Value 4000litres,
dept 3m value 6000,
Dept 4m value 8000 litres
find the value of 3.78m..pls Help me out🙏🏾 with the answers I need it in an interview pls

looks like you data has the form

(1,1000)
(2,4000)
(3,6000)
(4,8000)

it appears the last 3 follow a linear function with the first an outlier
lets try a ratio
(3,6000)
(3.78,y)
(4,8000)

(y-6000)/(8000-6000) = (3.78-3)/(4-3), note: just doing slopes
(y-6000)/2000 = .78
y - 6000 = 1560
y = 7560