A child attempts to drink water through a100cm long straw bu

A child attempts to drink water through a100cm long straw but finds
that the water rises only 75cm
By how much has the child reduced the pressure in her mouth below
atmospheric pressure?
express your answer using two significant figures
P atmos- P mouth= atm
一个小孩用一个100厘米的吸管喝水，但是只能吸到75厘米，就问，这个小孩在标准大气压下需要多少的压力才能吸到，求大气压强和小孩吸力压强的差