Knitting pattern adjustment help

[Thighdentitycrisis]

I’m knitting a sleeveless v neck vest. I already made one true to the pattern. Now it’s a bit of an experiment adjusting the original pattern to a different yarn and gauge.

All going well until I reached shaping the top of back piece, and I just can’t get my head round the maths

original pattern 97 st :
R1 K87, turn
R2 K93 turn
R3 K77 turn
R4 K77 break wool, slip all st onto one needle, rejoin wool, c/o

my pattern has 54 stitches, can anyone help me convert ?

Would thinking of this in terms of percentages help you?

So the original row 1, the % of stitches knitted is 90%
so 90% of 54 rounds up to 49.

Yes! Thanks for answering I did work it out exactly this way in the end :)