$(20$ pts$)4.$ In order to measure flow rates for the flow section in Figure $1,$ a propeller type current meter is used for which calibration equation is $V(\frac{m}{s})=0\mathrm{.}05n-0\mathrm{.}5.$ Where n is the number of the rotation of propellers. Using the measured rotations in Table $3$

y : The last digit of the sum of the digits of your student number.

Figure $1$: Cross section and measurement points.

Table $3$: Propeller readings

$\backslash$table$[[$Points$,1,2,3,4],[$Number of rotations,$25+y,30+y,120+y,100+y$

y$=4$