please help me solving these just send me the picture and the writing should be clear to understand

1.A mason wants to start building a stone pyramid the base of which has 551 blocks and the top 26th layer has only 1. If the number of blocks on each layer follow an arithmetic sequence, how many blocks should he get?

2.A farmer has to plant seeds in a triangular field. He knows that the middle row, row 26, needs 4025 seeds, and that the last row needs 7525 seeds. If the number of seeds planted in each row follows an arithmetic series, how many total seeds does he need? Hint: there are 51 rows in total.