7. This year, the water in a reservoir dropped by 60%. For the original water level to be restored next year, by what percent must the remaining reserves increase?

Given: Water in a reservoir dropped by 60%

Step-by-step explanation:

let the total water level of reservoir be 100.

then, in first year

the water reservoir dropped = 60% of 100

                                               = * 100

                                               = 60

therefore, total water level needed to be restored till next year= 100

remaining water level to restore till next year= 100-60

                                                                           =40

                                                       percentage= * 100

                                                                         =40%

25

step-by-step explanation: