Mirza Basheeruddin Mehmood, son of Mirza Ghulam Ahmad and the 2nd Khalifa of Qadian, wrote a book called Da’awat-ul-Ameer (Invitation of Ameer). Following is a quotation from this book.
“There is another important statement by the Holy Prophet. During his last illness, the Holy Prophet said to his daughter Fatima: ‘Once a year Gabriel used to recite the Quran to me. This year he recited twice. He also told me that every succeeding Prophet has lived upto half the age of his predecessor. He told me that Jesus, son of Mary, lived to 120 years. Therefore, I think, I may live to about 60 years.’ The statement is an inspired one. The Holy Prophet does not say anything on his own but reports what he received from Gabriel, the angel of revelation. The important part of the statement is that Jesus lived to 120 years. According to the New Testament records, Jesus was about 32 or 33 years old when the event of the Cross took place and Jesus “ascended ” to Heaven. If Jesus has really ‘ascended’ his age up to the time of the Holy Prophet comes to about 600 years, not 120. If what Gabriel told Holy Prophet is true, then Holy Prophet should have lived for at least 300 years. But he lived only for 63 years. Yet, according to Gabriel Jesus lived for 120 years. This important statement by the Holy Prophet proves that to think that Jesus is alive is against the teaching of Holy Prophet, against what was revealed to him by God. In view of all this, how can we be persuaded to believe that Jesus is alive? How can we deny anything which the Holy Prophet has taught so clearly?” (Invitation to Ahmadiyyat or Da’awat-ul-Ameer, p.17)
Now in the light of above statement, if what Mirza Basheer has written is true then let us very quickly calculate the age of some Prophets. Although there have been 124,000 of them, we will just take a few famous ones. We come to the following conclusion:-
Hazrat Adam (pbuh) 122880 years old
Hazrat Seth (pbuh) 61440 years old
Hazrat Noah (pbuh) 30720 years old
Hazrat Abraham (pbuh) 15360 years old
Hazrat Ishmael (pbuh) 7680 years old
Hazrat Jacob (pbuh) 3840 years old
Hazrat Joseph (pbuh) 1920 years old
Hazrat Moses (pbuh) 960 years old
Hazrat David (pbuh) 480 years old
Hazrat Solomon (pbuh) 240 years old
Hazrat Jesus (pbuh) & 120 years old
Hazrat Muhammad (pbuh) 60 years old
then Mirza Ghulam Ahmad sahib should be 30 years of age.? The next prophet wud be 15 the next 7 n half and so on. Because according to Ahmadiyyah belief there is still possibility of nabuwah and more prophets can still arise, unfortunately from Ahmadiyyah only.