You
80%
Partner
40%
Team clears it
32%
Tries for 5 tricky bits
~16
Both must
Share work
One carries
Assist for partner: off
Toy model, illustrative numbers. Sliders = chance each player clears one tricky section per try. Both must = you × partner; share = the average; carry = 1 − (both miss). Assist = +25 points for your partner.