Please help me with this answer

Out of the (400) students in the final year in senior secondary School (300) are offering biology and (190) are offering chemistry
(1) how many students are offering both biology and chemistry. If only (70) students are neither biology or chemistry .
(2)how many students are offering at last out of Biology or chemistry.

You should repost this with math as the subject. This is not chemistry and it is not biology.